Open AccessProperties of the Charge‐Transfer Transition Observed in Glyceraldehyde‐3‐phosphate Dehydrogenase from Sturgeon Muscle Alkylated by 3‐Chloroacetylpyridine — adenine Dinucleotide
Author(s) -
BRANLANT Guy,
TRITSCH Denis,
EILER Brigitte,
WALLEN Leif,
BIELLMANN JeanFrancois
Publication year - 1982
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1982.tb07069.x
Subject(s) - chemistry , covalent bond , dehydrogenase , amino acid , alkylation , glyceraldehyde 3 phosphate dehydrogenase , ionic strength , stereochemistry , crystallography , enzyme , biochemistry , organic chemistry , catalysis , aqueous solution
An absorption band at 340 nm is shown to be formed concomitantly with the covalent bond between the affinity label 3‐chloroacetylpyridine‐adenine dinucleotide (clac 3 PdAD + ) and glyceraldehyde‐3‐phosphate om sturgeon. This band corresponds to a charge‐transfer transition. Its intensity depends upon the pH and the ionic strength but is almost independent of the nature of the anions present in the medium. The pH dependence shows an inflexion point at pH 7.1. This result suggests the participation of a residue with a p K a of 7.1 within the active site of the enzyme in the formation of this transition. Using various techniques, the amino acid alkylated by clac 3 PdAD + is s OW be the essential Cys‐149, thus excluding the participation of this residue in the formation of the charge‐transfer transition. On the other hand, the modification of Cys‐153 seems not to affect this charge‐transfer band. Other possible donors are proposed, such as the invariant His‐176 or Tyr‐317 residues. These amino acids might be implicated in the formation of the Racker band.