Stability and activity modulation of chymotrypsins in AOT reversed micelles by protein-interface interaction: interaction of alpha-chymotrypsin with a negative interface leads to a cooperative breakage of a salt bridge that keeps the catalytic active conformation (Ile16-Asp194).
The stability of alpha-chymotrypsin and delta-chymotrypsin was studied in reversed micelles of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in isooctane. alpha-Chymotrypsin is inactivated at the interface and at the water pool, while delta-chymotrypsin is inactivated only at the water pool. The mechanism of inactivation at the interface is related to the interaction of N-terminal group alanine 149 (absent in delta-chymotrypsin) with the negative interface. The dependence of enzyme activity on water content of these two enzymes in reversed micelles of AOT is also related with the interface interaction, since delta-chymotrypsin does not have a bell-shaped curve as observed for alpha-chymotrypsin.
Almeida
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FC
Departamento de Bioquímica-Instituto de Química, Universidade de São Paulo, Cidade Universitária, Caixa Postal 20780, CEP 01498-970 São Paulo-SP, Brasil. falmeida@server.bioqmed.ufrj.br
Valente
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AP
Chaimovich
H
H
D000818:Animals; D002384:Catalysis; D002417:Cattle; D002918:Chymotrypsin / Q000737:chemistry* / Q000378:metabolism*; D004143:Dioctyl Sulfosuccinic Acid; D004795:Enzyme Stability; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008823:Micelles; D010179:Pancreas / Q000201:enzymology; D011487:Protein Conformation; D013501:Surface-Active Agents
D007527:Isoenzymes; D008823:Micelles; D013501:Surface-Active Agents; D004143:Dioctyl Sulfosuccinic Acid; D002918:Chymotrypsin