Biochemistry (Washington) 1975-09-23

The uncatalyzed rates of enolization of dihydroxyacetone phoshate and of glyceraldehyde 3-phosphate in neutral aqueous solution. The quantitative assessment of the effectiveness of an enzyme catalyst.

A Hall, J R Knowles

Index: Biochemistry 14(19) , 4348-53, (1975)

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Abstract

By a combination of methods involving enzyme-catalyzed reactions and classical iodination techniques it has been possible to obtain all the relevant rate constants for the uncatalyzed interconversion of dihydroxyacetone phosphate and D-glyceraldehyde 3-phosphate via their common enediol intermediate. These rate constants are compared with those for the individual steps of the triosephosphate isomerase catalyzed reaction, and a quantitative picture of the effectiveness of the enzyme as a catalyst has been delineated. It is apparent that the enzyme increases the enolization rate of dihydroxyacetone phosphate by a factor of more than 10(9) over that of the uncatalyzed reaction.