Specific labeling of the essential cysteine residue of L-methionine .gamma.-lyase with a cofactor analog, N-(bromoacetyl)pyridoxamine phosphate
- 8 March 1988
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 27 (5), 1587-1591
- https://doi.org/10.1021/bi00405a029
Abstract
L-Methionine .gamma.-lyase from Pseudomonas putida is composed of four identical polypeptide chains and contains four cysteinyl residues per subunit. We have found one of them catalytically essential by its specific cyanylation with 2-nitro-5-thiocyanobenzoic acid. We have shown its essentiality also with N-(bromoacetyl)pyridoxamine 5''-phosphate (BAPMP), which is a cofactor analogue and also an affinity-labeling agent. The kinetic data show that the apoenzyme forms a binary complex with BAPMP prior to covalent binding. The stoichiometry of inactivation was 1 mol of BAPMP per subunit. We have shown that the cysteine residue modified with BAPMP is identical with that labeled specifically with [14C]iodoacetic acid. The amino acid sequences of the peptides containing the essential cysteine residue and the lysine residue to which pyridoxal 5''-phosphate is bound were determined by automated Edman degradation.This publication has 3 references indexed in Scilit:
- Proton nmr studies of substrate hydrogen exchange reactions catalyzed by L-methionine .gamma.-lyaseBiochemistry, 1985
- Suicide inactivation of bacterial cystathionine .gamma.-synthase and methionine .gamma.-lyase during processing of L-propargylglycineBiochemistry, 1979
- Catalytic action of L-methionine .gamma.-lyase on selenomethionine and selenolsBiochemistry, 1979