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COD (GADUS MORHUA) TRYPSIN HEAT INACTIVATION: A REACTION KINETICS STUDY
Author(s) -
AMIZA MAT AMIN,
GALANI DEPSINA,
OWUSUAPENTEN RICHARD K.
Publication year - 1997
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1997.tb00209.x
Subject(s) - gadus , chemistry , trypsin , kinetics , autolysis (biology) , order of reaction , chemical kinetics , reaction rate constant , limiting , chromatography , biochemistry , enzyme , biology , fishery , fish <actinopterygii> , mechanical engineering , physics , quantum mechanics , engineering
The heat inactivation of cod (Gadus morhua) trypsin was examined at 40–55C by nonlinear regression (NLR) analysis according to 1st‐order, n‐th order, or consecutive reaction kinetics. At 40C Cod trypsin was inactivated by a 2nd‐order reaction; n = 2 (±0.014) with a pseudo rate constant (k′) of 6.46 (±0.04) × 10 −4 (s −1 ). The order of reaction decreased with increasing temperature; n = 1.54 (±0.003) at 45C, n = 0.8 (±0.005) at 50C or n = 0.64 (±0.014) at 55C. At 45–55C the consecutive model also indicated 1st‐order inactivation kinetics. SDS‐PAGE analysis showed that with progressive heating the concentration of cod trypsin decreased and there was an appearance of lower molecular weight polypeptides. The results are consistent with a heat inactivation process involving trypsin autolysis. A mechanism for cod trypsin heat inactivation is proposed which accounts for the observed 1st‐order or 2nd‐order reaction kinetics as limiting cases.