PURIFICATION AND CHARACTERIZATION OF CHYMOTRYPSIN FROM PENAEUS-VANNAMEI (CRUSTACEA, DECAPODA)

?he purification and characterization of a chymotrypsin from the hepat opancreas of the white shrimp Penaeus vannamei is described. Only one chymotrypsin was detected in contrast to other shrimp that have two ma jor forms. P. vannamei chymotrypsin has a molecular mass of 33.2 kDa a nd a pi of 3,1. The molecular mass is high relative to other penaeid c hymotrypsins, The proteinase is acid labile and exhibits optimum activ ity at pH 8, The enzyme is thermostable both at 25 and 37C, It is a se rine proteinase, Phenylmethylsulphonyl fluoride and soybean trypsin in hibitor blocked the activity of the enzyme, and it was not affected by chymotrypsin inhibitors such as tosyl-PheCH(2)Cl or benzyloxycarbonyl -Phe-CH2Cl. Protein profiles of the hepatopancreas from two population s varied and this is suspected to be caused by differences in the expr ession of chymotrypsin in the white shrimp.