What is the role of Glu 270 and Arg 145 in catalysis? E270 acts as a GBC (general base catalyst) in step one and as a GAC (general acid catalyst) in step two. R145 provides specific ion-ion interactions with the C-terminal carboxylate of the substrate.

There are two proposed mechanisms for the catalytic function of carboxypeptidase A. The first is a nucleophilic pathway involving a covalent acyl enzyme intermediate containing active site base Glu-270. Evidence for this anhydride intermediate is mixed; Suh and colleagues isolated what is assumed to by the acyl intermediate.

Nov 13, 1998 · Modelling studies suggest that a key residue within the active site is Glu-270, which acts as a bidentate ligand ligating the two iron atoms (13, 14). The remaining ligands are a histidine, a monodentate aspartate, and water co-ordinated to Fe1 and a histidine, a glutamate, and water to Fe2.

2 days ago · What is the role of Glu 270 and Arg 145 in catalysis? E270 acts as a _________ in step one and as a ___________ in step two. R145 provides specific ______ interactions with the C-terminal ______ of the substrate. This confers specificity for cleavage of the C-terminal residue from the peptide substrate.

Model-ling studies suggest that a key residue within the active site is Glu-270, which acts as a bidentate ligand ligating the two iron atoms (13, 14). The remaining ligands are a histidine, a mono-dentate aspartate, and water co-ordinated to Fe1 and a histi-dine, a …

These results include the number (307) of amino acid residues in CPA (alpha), the identities of the residues (Arg 145, Glu 270, and Tyr 248) shown by the X-ray study to be involved in substrate binding and catalysis, and the existence of a disulfide bond.

acyl enzyme intermediate with active-site base Glu-270 (hence, an anhydride), subsequently labile to hydrolysis; or (2) a promoted-water pathway involving the attack

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Nov 13, 1998 · Mutation of a conserved glutamate (Glu-270), previously postulated to be a bridging ligand within the active site, to asparagine abolishes catalytic activity because mitochondria containing the E270N mutant protein do not exhibit antimycin A-resistant respiration.

Dec 1, 1998 · Mutation of a conserved glutamate (Glu-270), previously postulated to be a bridging ligand within the active site, to asparagine abolishes catalytic activity because mitochondria containing...