658 results about "Phenylalanine" patented technology

The invention relates to the technical field of bioactive peptides, in particular to a novel multifunctional collagen-like tripeptide and application thereof, an amino acid sequence contains multiple combinations, X can be selected from multiple components, 3-methoxy-4-hydroxyphenylalanine and the like are added, and the novel multifunctional collagen-like tripeptide can interact with specific proteins, activate related pathways and play multiple physiological functions and is applied to multiple fields. The collagen-like tripeptide has obvious advantages, innovates component expansion functions, improves the preparation method, improves the efficiency, reduces the cost, is matched with other components in the fields of beauty, health care and medicine, enhances the efficacy, realizes targeted delivery, and brings a new opportunity to related industries.

The present invention belongs to the technical field of biological prevention and treatment for viral diseases. Disclosed in the present invention are a tomato disease-resistant gene mutant, and the use thereof in the prevention and treatment of ToBRFV. It is found in the present invention that mutating the nucleotide at position 1927 of the coding region sequence of tomato Tm-22 gene from G to A, or mutating the amino acid at position 643 of the LRR domain of a protein that is encoded by tomato Tm-22 gene from glycine to arginine can remarkably reduce the accumulation level of ToBRFV capsid protein (CP). The gene (named Tm-22-Mut5) can serve as a novel ToBRFV resistant gene, and also retains the resistance to TMV, ToMV and ToMMV. The Tm-22-Mut5 and a pre-screened Tm-22-Mut3-1 mutant (tyrosine at position 767 of the LRR domain thereof is mutated to phenylalanine) undergo combinatorial mutagenesis to obtain a mutant Tm-22-Mut6. Analysis shows that the Tm-22-Mut6 can remarkably reduce the accumulation level of the ToBRFV capsid protein. Compared with the pFGCTm-22-Mut3-1 mutant obtained by screening in the previous research and the newly obtained mutant Tm-22-Mut5, the Tm-22-Mut6 has further improved resistance to ToBRFV.

The invention discloses a pichia pastoris engineering bacterium for synthesizing bakuchiol from de novo by converting methanol as well as construction and application of the pichia pastoris engineering bacterium. A heterologous p-coumaric acid synthesis pathway is introduced to neutral sites of different chromosomes of pichia pastoris, a high-yield p-coumaric acid strain is obtained through gene knockout, overexpression or heterologous expression of tyrosine and phenylalanine synthesis pathway key genes of a shikimic acid pathway, a heterologous bakuchiol biosynthesis pathway is introduced on the basis, and a high-yield p-coumaric acid strain is obtained. After overexpression of bakuchiol synthetase, endogenous overexpression or heterologous expression of MVA pathway key genes and exogenous acetyl coenzyme A supply pathway genes, methanol concentration optimization and bacterial strain His4 gene supplementation, the yield of bakuchiol is effectively increased to 91.2 mg / L and is increased by 59.8 times compared with that of an initial bacterial strain, and the yield of bakuchiol in a 15L fermentation tank reaches 692.8 mg / L. The method has the characteristics of high conversion efficiency, low production cost, convenience in preparation, wide industrial application prospect and the like.

The invention belongs to the technical field of bioengineering, and relates to a transaminase mutant, a recombinant genetically engineered bacterium and application of the transaminase mutant in catalytic synthesis of (R)-1-Boc-3-aminopiperidine.The transaminase mutant is obtained by conducting single-point or combined mutation on the 131 site and / or the 197 site of an amino acid sequence shown in SEQ ID NO.2; the mutation sites comprise that the 131 phenylalanine is mutated into aspartic acid, threonine or tyrosine, and / or the 197 lysine is mutated into arginine or leucine. Experimental results show that compared with wild type transaminase, the catalytic activity, the thermal stability and the organic solvent tolerance of the obtained mutants, especially single-point mutants MyTA1-F131Y and MyTA1-K197R and a combined mutant MyTA1-F131Y-K197R, are all remarkably improved, and compared with the wild type transaminase, the catalytic activity, the thermal stability and the organic solvent tolerance of the obtained mutants are all remarkably improved. The mutant MyTA1-F131Y-K197R can be used for efficiently catalyzing asymmetric amination of N-Boc-3-piperidone to synthesize (R)-1-Boc-3-aminopiperidine, the conversion rate of the (R)-1-Boc-3-aminopiperidine after the (R)-1-Boc-3-aminopiperidine reacts for 24 hours under the condition that the substrate concentration is 100 g / L can reach 90% or above, and the mutant MyTA1-F131Y-K197R has a good industrial application prospect.

The invention provides a method for detecting free amino acids in camellia oleosa seed oil, and establishes a method for detecting the free amino acids in the camellia oleosa seed oil based on ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS / MS), which comprises the following steps: pre-treating various amino acids in the camellia oleosa seed oil by using a non-derivation method; the problems of complicated operation, impurity interference and the like caused by derivatization are avoided, the extraction solvent is environment-friendly and economical, the extraction efficiency is high, and the pretreatment time is greatly shortened; then selecting a proper chromatographic column and a mobile phase, separating a plurality of free amino acids under the condition of not introducing excessive derivatization agents and ion pair reagents, and controlling the collection time to be 12 minutes. The method for detecting the free amino acids in the camellia oleosa seed oil has the characteristics of no need of derivatization treatment, simplicity and convenience in operation, high detection efficiency and good sensitivity and accuracy, and can effectively separate and detect 14 free amino acids such as alanine, phenylalanine and aspartic acid in the camellia oleosa seed oil.

The present application relates to a pyridoxal kinase mutant, a recombinant expression vector and a microbial cell and their applications, and belongs to the technical field of biological catalysis. In order to solve the problem of low product concentration in existing enzyme catalysis, a pyridoxal kinase mutant is provided, the amino acid sequence is selected from the amino acid sequence shown in SEQ ID NO. 1, the lysine at position 229 is mutated to alanine, phenylalanine, methionine, arginine, threonine, histidine, serine, tyrosine, valine, leucine, isoleucine, proline, asparagine, aspartic acid or glutamic acid; the pyridoxal kinase mutant is used for catalyzing pyridoxal to synthesize pyridoxal phosphate, and a recombinant expression vector and a microbial cell can be further formed. The present application has good enzyme activity, high product conversion rate, high concentration of pyridoxal phosphate obtained, and the concentration of the product catalyzed by the wild-type pyridoxal kinase to phosphorylate pyridoxal is obviously improved.

The invention is applicable to the technical field of biomedicine, and provides dipeptide-photosensitizer molecule co-assembled nanoparticles as well as a preparation method and application thereof. According to the invention, cationic diphenylalanine (CDP) and a biological cross-linking agent genipin are self-assembled to form a dipeptide carrier, and then the dipeptide carrier and a photosensitizer molecule chlorin e6 (Ce6) are co-assembled, so that nanoparticles with controllable size, controllable drug loading capacity and good biocompatibility are successfully prepared. The preparation method is simple and easy to implement, effectively solves the key problems that the traditional photosensitizer molecule Ce6 is poor in biocompatibility and easy to gather, not only can efficiently deliver Ce6, but also obviously improves the application safety and biocompatibility of Ce6. The Ce6 is almost free of dark toxicity under a dark condition, can play a strong photodynamic killing role under illumination, and greatly improves the possibility and application potential of the Ce6 in tumor photodynamic therapy by virtue of the flexible regulation and control advantages of the size and the drug loading capacity.

The invention belongs to the technical field of biological medicine, and particularly relates to application of phenylalanine in evaluating Kawasaki disease and treating effect thereof and application of a phenylalanine inhibitor in treating Kawasaki disease. According to serum non-targeted metabonomics analysis and verification of KD children and IVIG treated KD children, phenylalanine is highly expressed in KD children, and phenylalanine is remarkably reduced after IVIG treatment of KD and tends to healthy children. The phenylalanine can be used as a serological marker for evaluating the Kawasaki disease treatment effect and diagnosing IVIG second-line treatment, and is high in specificity and sensitivity. After the phenylalanine inhibitor is administered to a KD model mouse, the content of phenylalanine in serum is remarkably reduced and is consistent with the trend in serum of the KD mouse treated by IVIG, myrica tongues are remarkably relieved, arterial dilatation is slowed down, and expression of inflammatory factors is reduced. The phenylalanine inhibitor has the effects of treating Kawasaki disease, improving myrica rubra tongue and slowing down arterial dilatation.

The application discloses a formic acid dehydrogenase mutant and application thereof in catalyzing carbon dioxide reduction. Paracoccus The formic acid dehydrogenase from sp.MKU1 is mutated by a site-directed mutation technology Ps The arginine (Arg) at the 223th position of the FDH48 amino acid sequence is mutated into proline (Pro) or the proline (Pro) at the 242th position is mutated into phenylalanine (Phe), and the obtained mutants R223P and P242F have higher catalytic activity, can more effectively catalyze CO2 to generate formic acid in vitro, and have potential application values in efficient activation of CO2 and further conversion into other one-carbon compounds through cascade reactions.

The application discloses a kind of nano magnetic flocculants and its preparation method and application, belong to drinking water processing technical field, including the following steps: step S1, modified ferroferric oxide nanosphere is ultrasonically dispersed in ammonia alcohol solution, while stirring, slowly drop adding tetraethyl orthosilicate, continue stirring after drop, after centrifugal separation, wash, obtain silica coated ferroferric oxide nanoparticles;Step S2, phenylalanine modified chitosan is added into glacial acetic acid solution, after completely swelling and dissolving, add silica coated ferroferric oxide nanoparticles and ultrasonic treatment, under low pressure ultraviolet lamp, then with anhydrous ethanol wash purification, vacuum drying to constant weight, obtain nano magnetic flocculants;The method of the application is simple and easy to operate, the nano magnetic flocculants prepared can be quickly adsorbed to the surface of sulfonamide antibiotics, produce flocculation and can be magnetically separated, very suitable for trace sulfonamide antibiotics in drinking water source efficient removal.

In the first aspect, the present disclosure provides a Lactoferrin polypeptide fragment, where the Lactoferrin polypeptide fragment has an amino acid sequence shown in SEQ ID NO: 1. In the second aspect, the present disclosure provides a preparation method of the Lactoferrin polypeptide fragment, including: protecting amino acids using a 9-fluorenylmethoxycarbonyl (Fmoc) protecting group, coupling the amino acids with a P-hydroxymethylphenoxymethyl polyethylene resin (HMP resin) in an order of cysteine, alanine, leucine, cysteine, glutamate, threonine, asparagine, aspartate, asparagine, phenylalanine, leucine, leucine, asparagine, and lysine, and separating the HMP resin to obtain a target Lactoferrin polypeptide fragment. In the third aspect, the present disclosure further provides an anti-Lactoferrin antibody prepared using the Lactoferrin polypeptide fragment, and use of the Lactoferrin polypeptide fragment in preparation of an anti-Lactoferrin flow cytometric antibody and in preparation of a Lactoferrin detection product.

The invention discloses an amino acid composition for treating alopecia and application of the amino acid composition in preparation of a medicine for treating alopecia, and belongs to the field of medicine configuration products, the amino acid composition is composed of a targeting core intervention component and an auxiliary strengthening synergistic component, the targeting core intervention component is prepared from 30-50 parts of arginine, 50-155 parts of lysine and 50-120 parts of glutamic acid, and the auxiliary strengthening synergistic component is prepared from an auxiliary strengthening synergistic component and an auxiliary strengthening synergistic component. 10 to 40 parts of cysteine and 20 to 60 parts of leucine; the auxiliary strengthening synergistic component is prepared from 15 to 45 parts of tyrosine, 15 to 40 parts of glycine, 10 to 40 parts of glutamine, 20 to 35 parts of serine, 5 to 25 parts of alanine, 2 to 20 parts of aspartic acid and 15 to 35 parts of phenylalanine; the composition can be used as an active ingredient to be prepared into different dosage forms such as a pigmentum, a spray, an ointment and a liniment, is applied to prevention of alopecia and promotion of hair growth, and has a remarkable treatment effect.

According to the scheme, the invention provides the recombinant macrolide enzyme as well as the preparation method and the application thereof, the amino acid sequence of the recombinant macrolide enzyme is as shown in SEQ ID NO.1, and the recombinant macrolide enzyme is derived from an EreC esterase family of enterobacter hormaechei and is obtained through site-specific mutagenesis; the mutation sites are as follows: glutamic acid at the 44th site is mutated into asparagine, tyrosine at the 55th site is mutated into proline, proline at the 76th site is mutated into arginine, phenylalanine at the 153rd site is mutated into alanine, and serine at the 219th site is mutated into glutamic acid. The method is expected to remove macrolide antibiotic pollution, and has good economic benefits and practical values.

The invention discloses application of copper-amino acid nano enzyme in preparation of anti-inflammatory drugs, and relates to the technical field of biomedical new materials, amino acids comprise glycine, arginine, histidine, threonine, phenylalanine and cysteine; the ratio of the amino acid to the copper ions is 1: (0.5-5), and the synthesis temperature of the copper-cysteine nano enzyme is 25-125 DEG C. The copper-amino acid nano-enzyme library established by the invention has efficient hydroxyl free radical, superoxide free radical and hydrogen peroxide scavenging activity; wherein the copper-cysteine nano-enzyme shows the highest enzymatic activity, and shows low toxicity and good biocompatibility in both the cell level and the animal level; meanwhile, the copper-cysteine nano-enzyme also shows anti-inflammatory activity and anti-oxidative stress activity, can remarkably improve cell inflammation and body inflammation, relieves and treats dextran sodium sulfate induced mouse ulcerative colitis, and can be further applied to preparation of drugs for treating inflammatory bowel diseases.

The invention relates to the technical field of biological catalysis, and discloses an M88F mutant enzyme for preparing rebaudioside I. The enzyme is obtained by the following mutations generated by UGT76G1: M88F: methionine of the 88th amino acid sequence of UGT76G1 is mutated into phenylalanine; and the substrate rebaudioside A (RA) can be efficiently and directionally converted into rebaudioside I (RI) with higher value. In an optimized reaction system, the conversion rate stably reaches 40%, and the catalytic efficiency is improved by more than 5-8 times compared with the common reference enzyme. The enzyme preparation has the characteristics of high catalytic activity, mild reaction conditions, simplicity and convenience in operation and the like, shows good stability and reproducibility in laboratory research and large-scale production, and has a wide industrial application prospect.

Disclosed herein are inhibitors of 4-hydroxyphenylpyruvate dioxygenase (HPD or HPPD) that have decreased inhibitory activity against sepiapterin reductase (SPR). Disclosed herein are methods of administering an HPD inhibitor alone or in combination with a diet low in tyrosine and / or phenylalanine, with or without dihydrobiopterin (BH2) and / or tetrahydrobiopterin (BH4) supplementation and / or monoamine salvage therapy. The compounds of the present disclosure can be used to treat conditions responsive to modulation or inhibition of HPD, such as inborn errors of metabolism, including tyrosinemia. The compounds of the present disclosure can also be used as herbicides to control weeds.

The invention discloses an engineered glycosyl transferase and application thereof in efficient preparation of triterpenoid saponin. The engineered glycosyl transferase is obtained by mutating serine at the 15th site of UGT74AC1 enzyme into alanine, mutating histidine at the 47th site into aspartic acid, mutating leucine at the 48th site into valine, mutating alanine at the 180th site into serine, mutating histidine at the 180th site into aspartic acid, mutating histidine at the 180th site into aspartic acid, mutating histidine at the 180th site into aspartic acid, mutating histidine at the 180th site into aspartic acid The mutant is obtained by mutating serine at the 332 site into proline, phenylalanine at the 367 site into tryptophan and lysine at the 420 site into arginine. According to the invention, the glycosyl transferase with high catalytic activity is obtained by modifying an enzyme engineering technology, and good application of the glycosyl transferase in synthesis of triterpenoid saponin is realized. The glycosyl transferase disclosed by the invention can also be coupled with sucrose synthase, or coupled with N-acetylhexosamine kinase and N-acetylglucosamine-1-uridine phosphate transferase, and acetylglucosamine is used as a glycosyl donor, so that cascade production of triterpenoid saponin with lower cost and higher efficiency is realized.

The invention provides a method for regulating and controlling aroma of grape fruits through an exogenous plant growth regulator, which comprises the following steps of: spraying three exogenous plant hormones, namely methyl jasmonate, phenylalanine and strigolactones, on 'Hanxiangmi' grape fruits with strong rose aroma, and analyzing the aroma composition and content of the treated grape fruits. The result shows that the rose fragrance intensity of the'Hanxiangmi 'grapes is enhanced after the jasmonic acid methyl ester treatment; after strigolactones treatment, components such as alpha-terpilenol, beta-ionone, nonanoic acid, geraniol and the like in grape fruits are prominent, so that the treated grapes are converted into mixed fragrance type grapes with flower fragrance, fruit fragrance and grass fragrance, and the fragrance layers are rich; and the treatment effect of phenylalanine is not obvious. The invention provides a reference for the research of strigolactone in fruit quality.

The invention relates to the technical field of gene engineering and enzyme engineering, in particular to a beta-glucosidase mutant with high catalytic activity and application of the beta-glucosidase mutant. The sequence of the beta-glucosidase mutant is obtained by carrying out any one of the following mutations on an amino acid sequence as shown in SEQ ID No.1: respectively mutating proline at the 95th site and arginine at the 178th site into cysteine; phenylalanine at the 98th site and arginine at the 178th site are respectively mutated into cysteine. The obtained mutants P95C / R178C and F98C / R178C have high enzyme activity, ginsenoside Rb1 can be converted into CK, the conversion efficiency is respectively improved by 83.52% and 105.79% compared with that of wild beta-glucosidase, and the industrial application of enzymatic conversion of rare ginsenoside CK is promoted.

A gene editing protein variant is capable of reducing a gene editing off-target rate. The variant is an unnatural protein with cis-cleavage activity, and the variant has reduced trans-cleavage activity as compared to a wild-type gene editing protein thereof. Furthermore, the variant is mutated at one or more of cleavage activity-related core amino acid sites of the wild-type gene editing protein selected from the following: a phenylalanine (F) site corresponding to the 1081st position of FnCas12a; and / or a lysine (K) site corresponding to the 1069th site of the FnCas12a. The variant can have cis-cleavage activity and reduced trans-cleavage activity. Moreover, the gene editing protein variant or a gene editing system having the gene editing protein variant can significantly reduce the gene editing off-target rate.

The invention discloses a salicylic acid decarboxylase mutant and application of the salicylic acid decarboxylase mutant in degradation of salicylic acid. The mutant is obtained by carrying out site-specific modification on salicylic acid decarboxylase NahG, and specifically, valine at the 46th site, tyrosine at the 380th site and leucine at the 382nd site of an amino acid sequence shown in SEQ ID NO.2 are mutated into cysteine, phenylalanine and phenylalanine at the same time. The mutant shows remarkably improved catalytic efficiency, and salicylic acid can be efficiently and thoroughly decarboxylated and converted into catechol under mild conditions. The invention also provides a coding gene, a recombinant vector and an engineering bacterium of the mutant. The mutant not only can be used for efficient bioremediation of salicylic acid pollution, but also can effectively break through and accelerate a naphthalene catabolism pathway due to the characteristic of directionally generating catechol, and has important application value in the fields of environmental pollution abatement and biological catalysis.

The invention relates to the technical field of bioengineering, in particular to a penicillin G acylase mutant, polynucleotide, an expression vector and application. The penicillin G acylase mutant is obtained by carrying out site-directed mutagenesis on a wild type penicillin G acylase gene of parent Escherichia coli, and carrying out site-directed mutagenesis on the wild type penicillin G acylase gene to obtain the penicillin G acylase mutant. Phenylalanine (F) at the 24th site of an alpha chain, proline (P) at the 383rd site of a beta chain, threonine (T) at the 384th site of the beta chain, glutamic acid (G) at the 385th site of the beta chain and serine (S) at the 386th site of the beta chain of the penicillin G acylase are introduced and mutated by a whole plasmid PCR (Polymerase Chain Reaction) technology to obtain mutants. When the penicillin G acylase mutant obtained by the invention is used for catalyzing methyl mandelate and 3-(1-methyl-1H-tetrazole-5-yl) thiomethyl-7-aminocephalosporanic acid to synthesize cefamandole, the synthesis activity is improved, and meanwhile, the side reaction rate is greatly reduced.

The invention belongs to the technical field of enzyme mutants, and discloses a mutant of lycopene cyclase and application of the mutant, glutamic acid at the 321 site of wild type lycopene cyclase which is derived from arabidopsis and has an amino acid sequence as shown in SEQ ID NO.1 is mutated into lysine, phenylalanine at the 319 site of the wild type lycopene cyclase is mutated into leucine, cysteine at the 323 site of the wild type lycopene cyclase is mutated into alanine, and the mutant of the lycopene cyclase is obtained. 1, and the lycopene cyclase mutant with the amino acid sequence as shown in SEQ ID NO. 2 is obtained. BTS1, CrtB and CrtI are integrated into a saccharomyces cerevisiae BY4741 strain, and a chassis strain ZA1 for stably producing alpha-carotene precursor lycopene is constructed; mutant expression plasmids are constructed, positive clone strains are screened out, and the epsilon-cyclization ability of mutant enzymes is remarkably higher than the beta-cyclization ability; the method comprises the following steps: by taking lycopene as a substrate, constructing an expression vector lipid droplet surrounding protein PET10; gene PAH1, DGA1 and Cat2 related to TAG synthesis and perilipid droplet protein PET10 are constructed on an expression vector and converted into ZA1, and when lycopene is used as a substrate, the efficiency of catalytic production of alpha-carotene is improved.

The invention relates to aspartate kinase for relieving feedback inhibition of L-threonine and application of aspartate kinase, and belongs to the field of enzyme engineering and metabolic engineering. The mutant is obtained by carrying out E253K and / or K507E mutation on the basis of wild type aspartate kinase as shown in SEQ ID NO.1, the enzyme activity of the mutant is not obviously changed under the condition that the concentration of L-threonine is 0-12 mmol / L, and the feedback inhibition effect of L-threonine on the mutant is relieved. The method can be widely applied to synthesis of essential amino acids including L-threonine, L-tryptophan, L-isoleucine, L-lysine, L-leucine, L-valine, L-methionine, L-phenylalanine and the like.

A CVB virus expression vector comprising a PIV5 W3A viral genome comprising a mutation at amino acid residue S157 or S156 of the P / V gene and a deletion of the small hydrophobic (SH) gene of the PIV5 W3A viral genome, wherein the amino acid substitution at amino acid residue S157 or S156 comprises a substitution of serine (S) with phenylalanine (F) or asparagine (N), and the SH gene has a deletion of the SH open reading frame or the entire SH gene transcription unit. The CVB virus expression vector expresses a heterologous polypeptide, including SARS-CoV-2 spike (S), and / or nucleocapsid (N) and / or membrane (M) proteins, RSV fusion protein (F), or other antigens.

The invention discloses tranexamic acid-polypeptide conjugate as well as a preparation method and application thereof, and belongs to the technical field of biology. The invention relates to a tranexamic acid-polypeptide conjugate or a salt thereof. The structure of the tranexamic acid-polypeptide conjugate is as shown in the following formula (I): TXA-Xaa1-L-phenylalanyl-D-arginyl-L-tryptophanyl-Xaa2-NH2 (I), wherein TXA-Xaa1-L-phenylalanyl-D-arginyl-L-tryptophanyl-Xaa2-NH2 (I) is shown in the description; wherein TXA is 4-(aminomethyl) cyclohexane carbonyl, and TXA is 4-(aminomethyl) cyclohexane carbonyl; xaa1 is a chemical bond, a neutral amino acid residue or a hydrophilic linker; xaa2 is a chemical bond, a neutral amino acid residue or a hydrophilic linker. The tranexamic acid-polypeptide conjugate or the salt thereof disclosed by the invention can simultaneously block two key signal channels for melanogenesis to achieve a synergistic effect of '1 + 1gt, 2', and further improve the inhibition effect on melanogenesis.

An Fc-binding polypeptide with improved alkaline stability comprising a mutant of the Fc-binding domain of Staphylococcus protein A (SpA), said mutant being defined by SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 22, SEQ ID NO 51 or EQ ID NO 52, wherein at least the asparagine or serine residue at a position corresponding to position 11 in SEQ ID NO: 4-7 has been mutated to an amino acid selected from the group consisting of glutamic acid, lysine, tyrosine, threonine, phenylalanine, leucine, isoleucine, tryptophan, methionine, valine, alanine, histidine and arginine.

A Levodopa-selective sensor is provided. A continuous levodopa monitor is also provided. The levodopa sensor includes a sensor area having a working electrode with a levodopa-selective chemistry configured for at least partial implantation in a host. The sensor also includes at least one membrane adjacent the levodopa-selective chemistry. The at least one membrane includes an enzyme domain that at least one enzyme selected from a tyrosinase; a mutated tyrosinase with specificity towards I-3,4-dihydroxyphenylalanine; a dihydroxyphenylalanine 4,5-dioxygenase; a mutated dihydroxyphenylalanine 4,5-dioxygenase with specificity towards I-3,4-dihydroxyphenylalanine; and combinations thereof; a synthase enzyme with specificity towards I-3,4-dihydroxyphenylalanine; a mutated synthase enzyme with specificity towards I-3,4-dihydroxyphenylalanine; a 3,4-dihydroxyphenyl-acetaldehyde synthase; a mutated 3,4- dihydroxyphenyl-acetaldehyde synthase with specificity towards I-3,4-dihydroxyphenylalanine; a dioxygenase enzyme with specificity towards I-3,4-dihydroxyphenylalanine; and a mutated dioxygenase enzyme with specificity towards I-3,4-dihydroxyphenylalanine.

The invention belongs to the field of bionic electronic materials and application, and discloses a dipeptide amino acid sequence with a piezoelectric effect, a dipeptide piezoelectric fiber film is prepared from the dipeptide amino acid sequence through a drop casting method, a meniscus driving method and an electric field induction meniscus driving method, and the obtained fiber film is assembled into an application example of a piezoelectric generator. The amino acid sequence of the dipeptide with the piezoelectric effect is Fc-L-Phe-L-Phe-OH, in the formula, Fc is a ferrocene benzoic acid group, Phe represents phenylalanine, and L represents the chirality of used amino acid. The dipeptide micron fiber thin film which is large in area and closely arranged is prepared by utilizing a drop casting method, a semilunar driving method and various methods of introducing a regulation and control electric field in a semilunar driving method membrane preparation process. The obtained fiber film is assembled into a piezoelectric generator of a sandwich structure, the piezoelectric output performance of the piezoelectric generator is closely related to the preparation method of the fiber film, and the piezoelectric performance of the dipeptide fiber film can be remarkably improved through an electric field induction meniscus driving method.

The present invention relates to a method of preventing or alleviating the effect of abiotic stress in a plant, which involves applying to the plant, including plant seeds or to a plant growth medium, an effective amount of phenylalanine and / or any salt or solvate thereof and a seaweed extract.