Thiol-blocking reagents and phosphate acetyltransferase catalysis, and the assessment of protection by adsorbed molecules.

Phosphate acetyltransferase (EC 2.3.1.8) is shown to be unusually sensitive to thiol-blocking reagents, and one or more thiol groups probably catalyse the surface reaction. A novel method for assessing protection by adsorbed species is described. The adsorbed substrate molecules acetyl-CoA and phosphate are found to provide substantial protection against thiol-blocking reagents.