ISOLATION AND PROPERTIES OF TRYPSIN PC FR OM THE KING CRAB PARALITHODES CAMTSCHATICA

Trypsin PC from the hepatopancreas of the king crab Paralithodes camts chatica was isolated and purified to apparent. homogeneity by ion-exch ange chromatography on Aminosilochrom and DEAE-Sephadex and affinity c hromatography on arginine-agarose, The yield of the enzyme was 37.7%, and the purification degree was 21. Trypsin PC has a molecular mass of 29 kDa and pI < 2.5. It hydrolyses N-benzoyl-L-arginine p-nitroanilid e at the optimum pH of 7.5-8.0 and at the temperature optimum of 55 de grees C (K-m = 0.05 mM). Trypsin PC retained its activity within the p H range of 5.8-9.0 in the presence of Ca2+. The enzyme was inhibited b y the specific inhibitors of serine proteases diisopropyl fluorophosha te and phenylmethylsulfonyl fluoride, by the trypsin inhibitor N-tosyl -L-lysylchloromethylketone, and by the trypsin inhibitors from soybean and potato. Trypsin PC was found to hydrolyze amide bonds formed by c arboxylic groups of lysine and arginine in peptide substrates. The N-t erminal sequence of this enzyme is IVGGTEVTPG.