Amino acid sequence of an active site peptide of avian liver mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase.
Hydroxymethylglutaryl-CoA synthase is irreversibly inhibited by the active site-directed inhibitor 3-chloropropionyl-CoA. Enzyme modification has been postulated to involve alkylation of an active site cysteinyl sulfhydryl group. DEAE-Sephadex chromatography of tryptic digests prepared from enzyme inactivated using chloro[14C]propionyl-CoA suggested that bound radioactivity is localized on one peptide. Specificity of the modification was further demonstrated by reverse-phase high pressure liquid chromatography, which was used to isolate the radioactively labeled peptide in a chemically homogeneous form. Automated gas-phase Edman degradation techniques have been employed to confirm the assignment of cysteine as the inhibitor's target residue and to elucidate the sequence of amino acids which flank the 14C-carboxyethylated cysteine: Glu-Ser-Gly-Asn-Thr-Asp-Val-Glu-Gly-Ile-Asp-Thr-(Thr)- Asn-Ala-S-[14C]carboxyethylcysteine-Tyr-Gly-Gln-Thr-(Ala). These data represent the first assignment of active site structure for hydroxymethyl-glutaryl-CoA synthase.
Miziorko
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Behnke
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D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002645:Chickens; D003545:Cysteine / Q000032:analysis; D006904:Hydroxymethylglutaryl-CoA Synthase / Q000032:analysis*; D008930:Mitochondria, Liver / Q000201:enzymology*; D007652:Oxo-Acid-Lyases / Q000032:analysis*
D006904:Hydroxymethylglutaryl-CoA Synthase; D007652:Oxo-Acid-Lyases; D003545:Cysteine