2results about How to "Simplify purification operations" patented technology

The application discloses a green preparation method of 4,4'-difluorobenzophenone. The method uses 4,4'-difluorobenzene as raw material, potassium bromide as catalyst, acetic acid as solvent, and oxygen as oxidant, and 4,4'-difluorobenzophenone is generated in high selectivity through one-step oxidation under mild conditions. The application surprisingly finds that in the presence of potassium bromide, a new non-metallic catalytic oxidation system of potassium bromide / acetic acid / oxygen is used to realize high-efficiency and high-selectivity conversion of the C-H bond at the benzyl position. Compared with the traditional method, the application does not need to use a transition metal catalyst, does not need to use carbon tetrachloride and other materials damaging the ozone layer, and does not need to involve a dangerous intermediate such as a diazonium salt, the process route is short, the atomic economy is high, the product yield is high, the product purity is high, the catalyst is cheap and easy to obtain, and the application has excellent industrial application prospect and green chemistry characteristics.

The invention provides an enterokinase light chain recombinant protein and application and a method for efficient soluble expression of a recombinant enterokinase light chain, the enterokinase light chain recombinant protein is composed of more than two fusion proteins AgSg or mutants thereof and an enterokinase light chain or mutants thereof, the amino acid sequence of the fusion proteins AgSg is shown as SEQ ID NO.3, and the amino acid sequence of the fusion proteins AgSg is shown as SEQ ID NO.3. The amino acid sequence of the enterokinase light chain is as shown in SEQ ID NO. 1; according to the enterokinase light chain recombinant protein, a specific amount of fusion protein AgSg derived from the N end of spider silk sericin is fused with an enterokinase light chain or a mutant thereof in a series connection manner, so that the expression quantity of the enterokinase light chain or / and the mutant can be remarkably improved, and the enterokinase light chain or / and the mutant can be expressed in a soluble form; the defects that a traditional escherichia coli system is low in expression quantity and expression and purification are difficult in an inclusion body form are overcome, and the method can be applied to production of high-efficiency soluble enterokinase light chains.