A molecular model for interfacial activation in phospholipase A2.
Electrostatic calculations predict that amino-terminal conformation and ionisation contribute significantly to transition state stability in phospholipase A2, so that control of these factors by binding to aggregated substrate provides a plausible mechanism for interfacial activation. In particular, it is suggested that a part of the pH dependence of interfacial activity may arise from transient deprotonation of an ordered amino-terminus. Interface charge and the detailed structure of the interfacial complex are also predicted to influence catalytic activity. The model is compared with available biochemical data.
Warwicker
J
J
Food Macromolecular Science Department, Institute of Food Research, Reading Laboratory, UK. james.warwicker@bbsrc.ac.uk
D000818:Animals; D004789:Enzyme Activation; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D010179:Pancreas / Q000201:enzymology; D010741:Phospholipases A / Q000737:chemistry* / Q000378:metabolism*; D054467:Phospholipases A2; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D055672:Static Electricity; D013552:Swine; D013816:Thermodynamics
D010741:Phospholipases A; D054467:Phospholipases A2