“…The cellular mechanism responsible for decreased oxidative metabolism involves decreased mitochondrial enzyme activity, as was evidenced by specific decreases in the activities of citrate synthase (CS), malate dehydrogenase, and cytochrome oxidase Lin et al, 1992;Hsu et al, 1994]. Further studies showed that there was no decline in the activities of several cytosolic enzymes including creatine kinase, hexokinase, myosin ATPase, and phosphoribosyl transferase [reviewed in Levin et al, 1999a].…”