title: The effect of conditions of homogenization on the activity of pyruvate dehydrogenase and its stability in brain homogenates.
abstract: The activity of pyruvate dehydrogenase was higher in brain homogenates prepared by using a Potter-Elvehjem type homogenizer (79.0 +/- 2.38 nmol/min/mg of protein) than by using an Ultra-Turrax homogenizer (from 62.39 +/- 1.35 to 74.60 +/- 1.21 nmol/min/mg of protein). Different conditions of homogenization with the Ultra-Turrax had no significant effect on the activity of pyruvate dehydrogenase. Pyruvate dehydrogenase activity decreased significantly in brain homogenates maintained at 0 degrees C for short periods or stored at ?20 degrees C for several days. Marked differences in pyruvate dehydrogenase activities reported in earlier work have been attributed to its instability in brain homogenates. The results showed that pyruvate dehydrogenase is not a rate limiting enzyme in the metabolism of glucose in brain in vivo.
authors.affiliation: Department of Biochemistry, St George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, England.
authors.forename: M K
authors.initials: MK
authors.lastname: Gaitonde
authors.forename: E
authors.initials: E
authors.lastname: Murray