Phosphoenolpyruvate carboxykinase from guinea - pig liver mitochondria

Phosphoenolpyruvate carboxykinase was purified from mitochondria of guinea-pig liver by affinity chromatography on GMP-Sepharose. The enzyme was purified 100fold to a high degree of electrophoretic homogeneity asjudged by detection of a single protein band on sodium dodecyl sulphate/polyacrylamide gels. The yield was about 16%. The Mr of the purified enzyme was estimated to be 68 500 + 680 by analysis on sodium dodecyl sulphate/polyacrylamide gels. Antibodies raised in rabbits against the purified enzyme were highly specific for mitochondrial phosphoenolpyruvate carboxykinase and did not precipitate the cytosolic form of this enzyme from either rat or guinea-pig liver cytosol. The use of this antibody showed that starvation does not increase the amount of the enzyme. However, neonatal-development-dependent increase in its activity is shown to be mediated by accumulation of phosphoenol pyruvate carboxykinase-specific protein.