L-Phenylalanine derivatives are key components or intermediates of many anti-tumor compounds.L-4-Methylsulfonyl-phenylalanine may inhibit tumor cell proliferation.At present,L-phenylalanine derivatives are normally produced by chemical resolution or enzymatic method.In this work,the chiral compound L-4-methylsulphonyl-phenylalanine was prepared by enzymatic method from 4-methylsulphonyl-phenylpyruvate and L-aspartic acid.The influence of various factors on the biocatalysis was studied.The optimal temperatur...