Localization of pyruvate kinase isozymes in bovine kidney and comparison of these patterns with those of lactate dehydrogenases and aldolases.

ABSTRACT

Electrophoretic and immunofluorescence analysis were used to study the distribution of pyruvate kinase isozymes in the bovine kidney. Electrophoretic analysis demonstrated the presence of large amounts of K4 plus small amounts of K-M hybrids in cortical, medullary, and papillary sections cut from the kidney. Nearly all of the K-L hybrids seen in whole kidney extracts were found in cortical sections. Immunofluorescence of frozen sections revealed the presence of type L subunits in the tubules but the complete absence of this subunit type in flomeruli. Glomeruli do contain large quantities of pyruvate kinase isozymes, probably K4 and K-M hybrids, that cross-react with antibodies produced against type M pyruvate kinase. Type L-containing forms of pyruvate kinase and aldolase type B both appear to be found in cell types thought to be capable of catalyzing of gluconeogenesis, while type K pyruvate kinase and type A aldolase are found in predominantly glycolytic cell types of the kidney. Lactate dehydrogenase isozymic patterns appear to be less closely correlated with glycolytic versus gluconeogenic functions of the kidney but may be determined more directly by other metabolic functions.