Proteosynthesis vs. Proteolysis: How to Bias This Antagonism in Favor of Proteosynthesis

The choice between a proteosynthetic or proteolytic action for a given enzyme will depend primarily upon the energetics of the reactions to be catalyzed rather than upon the molecular mode of action of the enzyme. Certainly in the case where a protease-catalyzed reaction is allowed to proceed in aqueous solution under physiological conditions then, as commonly occurs for in vivo protease-controlled processes, proteolysis will largely predominate. In protease-catalyzed reactions the cleavage products of the general formula RCOO and +NH₃R' are usually more stable than the "intact" peptides of the general formula RCO-NHR'. Consequently, the concentration of RCOO and +NH₃R' will exceed that of the RCO-NHR' as soon as an equilibrium state has been attained. In the course of a protease-catalyzed process, the target product RCO-NHR' merely represents an intermediate form which is subject to subsequent secondary-hydrolysis. The catalytic action of many proteases is not confined exclusively to peptide bonds but also extends to ester- and amide bonds.