Comparison of the two purified allozymes (1B and 1A) of X-linked phosphoglycerate kinase in the mouse.

The two allelic isozymes (wild-type 1B and the electrophoretic variant 1A) of mouse X-linked phosphoglycerate kinase (PGK-1) have been purified by affinity chromatography. The following properties were determined for both forms: molecular weight, specific activity, nucleotide specificity, Km values of the four substrates, Ki of the ATP-ribosyladipoyldihydrazo-Mg complex, turnover number, activation energy, pH and ionic strength dependence, thermostability, content of free sulfhydryl groups, and antibody cross-reactivity. With the exception of specific activity and thermostability, both allozymes appear to be identical in all properties. The higher in vitro specific activity of the 1B allozyme may be due to the higher thermostability. No antigenic difference could be detected between the two allozymes.