Multichannel resonance Raman experiments on carboxypeptidase A catalyzed ester hydrolysis under cryoenzymological conditions

• Published in: Journal of the American Chemical Society Vol. 105; no. 23; pp. 6971 - 6973
• Main Authors: Hoffman, Stephen J, Chu, Samuel S. T, Lee, Ho Hi, Kaiser, E. T, Carey, P. R
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.11.1983
• Subjects: Analytical, structural and metabolic biochemistry; Biological and medical sciences; carboxypeptidase A; Enzymes and enzyme inhibitors; esters; Fundamental and applied biological sciences. Psychology; Hydrolases; hydrolysis; Raman spectroscopy; Hydrolysis; Reaction intermediate; Carboxypeptidase A; Enzyme; Reaction mechanism; Raman spectrometry; Low temperature
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja00361a044

Two principal reaction pathways have been considered in many laboratories for the action of carboxypeptidase A (CPA) on ester or peptide substrates. In one route, residue Glu-270, an essential active site group, acts as a general base catalyst; in the other pathway, Glu-270 acts as a nucleophile forming a transient enzyme-bound mixed anhydride intermediate. The present communication contains results the authors have obtained at low temperatures using multichannel resonance Raman (RR) spectroscopy to ascertain the extent to which acyl-enzyme intermediates accumulate in the CPA-catalyzed hydrolysis of ester substrates.