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Interaction of glyceraldehyde‐3‐phosphate dehydrogenase with SH‐containing compounds: evidence for the binding of l ‐cysteine and for the dependence of the binding on the functional state of the enzyme
Author(s) -
Schmalhausen Elena V.,
Muronetz Vladimir I.,
Nagradova Natalia K.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01151-4
Subject(s) - cysteine , glyceraldehyde 3 phosphate dehydrogenase , chemistry , dehydrogenase , tetramer , nad+ kinase , enzyme , glutathione , stereochemistry , biochemistry , binding site , hydrolysis , protonation , glyceraldehyde , organic chemistry , ion
Incorporation of l ‐[ 35 S]cysteine into rabbit muscle glyceraldehyde‐3‐phosphate dehydrogenase was detected following incubation of the enzyme in a mixture containing glyceraldehyde‐3‐phosphate, NAD + and the labeled cysteine. Insignificant binding occurred in the absence of either the substrate or NAD + , suggesting that formation of an acylated enzyme form was a prerequisite for the binding. Stoichiometry of the binding depended on the number of functioning active centers; up to 4 moles of l [ 35 S]cysteine bound per mole tetramer with fresh enzyme preparations. The l ‐[ 35 S]cysteine incorporation depended on pH and was maximal when a group having pK a of 8.5 is protonated. To clarify the relevance of this finding to the effect of SH‐containing compounds previously shown to decrease the rate of 3‐phosphoglyceroyl‐enzyme hydrolysis [Kuzminskaya et al., FEBS Lett. 336 (1993) 208–210], the pH‐dependence of the effect of glutathione on the hydrolysis rate was determined and found to be close to the pH‐dependence of l ‐[ 35 S]cysteine binding.