[Catalytic properties of three isoenzymes possessing pyrophosphatase activity, isolated from baker's yeast]

A kinetic study of inorganic pyrophosphatase isolated from brewer's yeast was done. It was shown that all three isoenzymes have the same pH-optimum and specificity with respect to substrate and metal activator. Statistical treatment of the kinetic data yielded equilibrium and catalytical constants, describing enzyme interaction with the metal activator and substrate. The catalytic properties of all three isoenzymes are similar to those of the baker's yeast pyrophosphatase. The fluoride inhibition pattern for inorganic pyrophosphatase from brewer's yeast is similar to that for the baker's yeast enzyme.