TY - JOUR
T1 - Pancreatic proteolytic enzymes from carp (Cyprinus carpio)-II. Kinetic properties and inhibition studies of trypsin, chymotrypsin and elastase
AU - Cohen, T.
AU - Gertler, A.
AU - Birk, Y.
PY - 1981
Y1 - 1981
N2 - 1. 1. Kinetic parameters for hydrolysis of specific synthetic substrates by carp trypsin, chymotrypsin and elastase were determined and compared to the respective mammalian enzymes. The kinetic properties of carp and mammalian trypsin and elastase were quite similar. The differences between the respective chymotrypsin were bigger probably due to minor differences in the vicinity of the catalytic site. 2. 2. The pH dependency of the enzymatic activities was determined in pH range 3-11. A typical bell-shaped curve was obtained with the respective pKas values of 6.37-6.78 and pKbs of 9.70-11.22. These most likely result from the dissociation of histidine-57 and the N-terminal amino group. 3. 3. Carp trypsin and chymotrypsin were irreversibly inhibited by amino acid and peptide chloromethylketones, thus further indicating the involvement of histidine-57 in the active site. A partial mapping of chymotrypsin with peptide chloromethylketones suggested the existence of an extended binding site. 4. 4. Inhibition of carp trypsin, chymotrypsin and elastase by eight naturally occurring high-molecular proteinase inhibitors resulted in inhibition curves resembling the respective bovine or porcine enzymes. It was, however, indicated thatcarp trypsin possibly interacts also with the chymotrypsin site of several inhibitors.
AB - 1. 1. Kinetic parameters for hydrolysis of specific synthetic substrates by carp trypsin, chymotrypsin and elastase were determined and compared to the respective mammalian enzymes. The kinetic properties of carp and mammalian trypsin and elastase were quite similar. The differences between the respective chymotrypsin were bigger probably due to minor differences in the vicinity of the catalytic site. 2. 2. The pH dependency of the enzymatic activities was determined in pH range 3-11. A typical bell-shaped curve was obtained with the respective pKas values of 6.37-6.78 and pKbs of 9.70-11.22. These most likely result from the dissociation of histidine-57 and the N-terminal amino group. 3. 3. Carp trypsin and chymotrypsin were irreversibly inhibited by amino acid and peptide chloromethylketones, thus further indicating the involvement of histidine-57 in the active site. A partial mapping of chymotrypsin with peptide chloromethylketones suggested the existence of an extended binding site. 4. 4. Inhibition of carp trypsin, chymotrypsin and elastase by eight naturally occurring high-molecular proteinase inhibitors resulted in inhibition curves resembling the respective bovine or porcine enzymes. It was, however, indicated thatcarp trypsin possibly interacts also with the chymotrypsin site of several inhibitors.
UR - http://www.scopus.com/inward/record.url?scp=0001092869&partnerID=8YFLogxK
U2 - 10.1016/0305-0491(81)90365-5
DO - 10.1016/0305-0491(81)90365-5
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AN - SCOPUS:0001092869
SN - 0305-0491
VL - 69
SP - 647
EP - 653
JO - Comparative Biochemistry and Physiology Part - B: Biochemistry and Molecular Biology
JF - Comparative Biochemistry and Physiology Part - B: Biochemistry and Molecular Biology
IS - 3
ER -