A test for the two-stage thermoinactivation model for chymotrypsin

RK Owusu, N Berthalon

Research output: Contribution to journal › Article

26 Citations (Scopus)

Abstract

Chymotrypsin was irreversibly inactivated at 30–130°C, pH 1.0–7.0 and in the presence of 0–4.0 m guanidine hydrochloride (GnHCl). The activation enthalpy for enzyme thermoinactivation (Δ#) at moderate temperatures, pH 4.0–7.0 and in ≤2 m GnHcl was 175–322 kJ mol−1. The activation entropy (ΔS#) was 244–734 J mol−1 K−1. Such results are compatible with enzyme unfolding being the rate-determining step for the thermoinactivation of native chymotrypsin. For chymotrypsin pre-unfolded at low pH, high temperature and/or in Gn/HCl, ΔH# was 30–40 kJ mol−1 and ΔS# was between −182 and −191 J mol−1 K−1. Therefore, thermoinactivation of pre-unfolded chymotrypsin is likely to involve covalent bond lysis as the rate-determining step. A biphasic Arrhenius plot was obtained for chymotrypsin thermoinactivation in 1.0–1.5 m GnHCl. Taken together, these results provide strong support for the two-stage model for enzyme thermoinactivation.
LanguageEnglish
Pages231
JournalFood Chemistry
Volume48
Issue number3
DOIs
Publication statusPublished - 1993

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Chymotrypsin
chymotrypsin
guanidines
Guanidine
testing
Enzymes
Chemical activation
Arrhenius plots
Temperature
Enzyme Activation
Covalent bonds
Entropy
enthalpy
entropy
enzymes
Enthalpy
temperature

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Owusu, RK ; Berthalon, N. / A test for the two-stage thermoinactivation model for chymotrypsin. 1993 ; Vol. 48, No. 3. pp. 231.
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title = "A test for the two-stage thermoinactivation model for chymotrypsin",
abstract = "Chymotrypsin was irreversibly inactivated at 30–130°C, pH 1.0–7.0 and in the presence of 0–4.0 m guanidine hydrochloride (GnHCl). The activation enthalpy for enzyme thermoinactivation (Δ#) at moderate temperatures, pH 4.0–7.0 and in ≤2 m GnHcl was 175–322 kJ mol−1. The activation entropy (ΔS#) was 244–734 J mol−1 K−1. Such results are compatible with enzyme unfolding being the rate-determining step for the thermoinactivation of native chymotrypsin. For chymotrypsin pre-unfolded at low pH, high temperature and/or in Gn/HCl, ΔH# was 30–40 kJ mol−1 and ΔS# was between −182 and −191 J mol−1 K−1. Therefore, thermoinactivation of pre-unfolded chymotrypsin is likely to involve covalent bond lysis as the rate-determining step. A biphasic Arrhenius plot was obtained for chymotrypsin thermoinactivation in 1.0–1.5 m GnHCl. Taken together, these results provide strong support for the two-stage model for enzyme thermoinactivation.",
author = "RK Owusu and N Berthalon",
year = "1993",
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language = "English",
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Owusu, RK & Berthalon, N 1993, 'A test for the two-stage thermoinactivation model for chymotrypsin', vol. 48, no. 3, pp. 231. https://doi.org/10.1016/0308-8146(93)90132-Y

A test for the two-stage thermoinactivation model for chymotrypsin. / Owusu, RK; Berthalon, N.

Vol. 48, No. 3, 1993, p. 231.

Research output: Contribution to journal › Article

TY - JOUR

T1 - A test for the two-stage thermoinactivation model for chymotrypsin

AU - Owusu, RK

AU - Berthalon, N

PY - 1993

Y1 - 1993

N2 - Chymotrypsin was irreversibly inactivated at 30–130°C, pH 1.0–7.0 and in the presence of 0–4.0 m guanidine hydrochloride (GnHCl). The activation enthalpy for enzyme thermoinactivation (Δ#) at moderate temperatures, pH 4.0–7.0 and in ≤2 m GnHcl was 175–322 kJ mol−1. The activation entropy (ΔS#) was 244–734 J mol−1 K−1. Such results are compatible with enzyme unfolding being the rate-determining step for the thermoinactivation of native chymotrypsin. For chymotrypsin pre-unfolded at low pH, high temperature and/or in Gn/HCl, ΔH# was 30–40 kJ mol−1 and ΔS# was between −182 and −191 J mol−1 K−1. Therefore, thermoinactivation of pre-unfolded chymotrypsin is likely to involve covalent bond lysis as the rate-determining step. A biphasic Arrhenius plot was obtained for chymotrypsin thermoinactivation in 1.0–1.5 m GnHCl. Taken together, these results provide strong support for the two-stage model for enzyme thermoinactivation.

AB - Chymotrypsin was irreversibly inactivated at 30–130°C, pH 1.0–7.0 and in the presence of 0–4.0 m guanidine hydrochloride (GnHCl). The activation enthalpy for enzyme thermoinactivation (Δ#) at moderate temperatures, pH 4.0–7.0 and in ≤2 m GnHcl was 175–322 kJ mol−1. The activation entropy (ΔS#) was 244–734 J mol−1 K−1. Such results are compatible with enzyme unfolding being the rate-determining step for the thermoinactivation of native chymotrypsin. For chymotrypsin pre-unfolded at low pH, high temperature and/or in Gn/HCl, ΔH# was 30–40 kJ mol−1 and ΔS# was between −182 and −191 J mol−1 K−1. Therefore, thermoinactivation of pre-unfolded chymotrypsin is likely to involve covalent bond lysis as the rate-determining step. A biphasic Arrhenius plot was obtained for chymotrypsin thermoinactivation in 1.0–1.5 m GnHCl. Taken together, these results provide strong support for the two-stage model for enzyme thermoinactivation.

U2 - 10.1016/0308-8146(93)90132-Y

DO - 10.1016/0308-8146(93)90132-Y

M3 - Article

VL - 48

SP - 231

IS - 3

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Owusu RK, Berthalon N. A test for the two-stage thermoinactivation model for chymotrypsin. 1993;48(3):231. https://doi.org/10.1016/0308-8146(93)90132-Y

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