Effect of aging on enolase from rat muscle, liver and heart

Muscle enolase (2-phospho-D-glycerate hydrolase, EC 4.2.1.11) and liver enolse from young and old rats have been purified to homogeneity and several properties of the respective young/old pairs, including Km, behavior on polyacrylamide gels, sensitivity to heat and specific activity have been compared. No difference has been detected. On the other hand, the heart isozyme shows an age-related increase in a heat-sensitive form of the enzyme. The results strongly support the idea tht some enzymes become altered in aging animals but others do not.