Enzymes and Surface Water
1*Retired from the Department of Medicine,University of Auckland, New Zealand, and from Genesis Research and Development Company, Auckland, New Zealand.
Key Words: allostery, protein folding, water
Received 12 February 2009; revised 17 March 2009; accepted 9 April 2009. Published 1 July 2009. Available online 1 July 2009.
The broad OH-stretch band of the infra red spectrum of liquid water is shown to comprise two overlapping bands peaking at 3250 cm-1 (the value in ice, and, presumably, strongly bonded water) and 3635 cm-1 (presumably weakly bonded water). The spectra also reveal the coexistence of zones of LDW and HDW in small-pored polymeric matrices. Possible mechanisms of reactions catalyzed by these zones of water associated with enzymes are described. There is a crucial functional connection between the force that drives folding of an enzyme and reactions that it catalyses. When water can move to abolish osmotic pressure gradients created by selective uptake of solutes into HDW or LDW, it does so with some decrease in the partition coefficients of the reactants. When water is prevented from moving, partition coefficients are unchanged, increased or transiently inverted. Examples of allostery and Michaelis-Menten kinetics (Matthews and van Holde, 1990) are given.