Open AccessRole of Sulphydryl Groups in Adenosine Deaminase
Author(s) -
Ronca G.,
Bauer C.,
Rossi C. A.
Publication year - 1967
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1967.tb00092.x
Subject(s) - iodoacetamide , chemistry , enzyme , reactivity (psychology) , adenosine deaminase , reagent , biochemistry , substrate (aquarium) , stereochemistry , organic chemistry , cysteine , biology , medicine , ecology , alternative medicine , pathology
The reactivity and the role of sulphydryl groups in adenosine deaminase have been investigated. In the sodium dodecylsulphate‐denatured enzyme 2.1 sulphydryl groups are titratable with p ‐mercuribenzoate. The native enzyme is inactivated by p ‐mercuribenzoate or phenylmercuric acetate and a stoichiometric relationship exists between the equivalents of mercaptide formed and the inactivation of the enzyme. Substrate analogs protect the enzyme against p ‐mercuribenzoate and phenylmercuric acetate inactivation. Iodoacetamide, iodoacetate, and N ‐ethylmaleimide, which do not affect the enzyme activity, do not react with sulphydryl groups. The results show that a sulphydryl group unreactive towards the alkylating reagents is essential in some way for the enzymatic activity. The lack of reactivity of the essential sulphydryl group with alkylating reagents suggests that the sulphydryl group may be contained in a hydrophobic region of the enzyme molecule.