Molecular size estimates of the human phosphoglucomutase isozymes by gel filtration chromatography

SUMMARY 1. Molecular sizes of the three sets of the human phosphoglucomutase isozymes attributable to the loci PGM1, PGM2 and PGM3 have been studied by gel nitration. 2. The PGM2 isozymes (M.W. C. 61,000) appear to be significantly larger than the PGM1 and PGM3 isozymes and the PGM3 isozymes (M.W. C. 53,000) appear to be slightly larger than the PGM1 isozymes (M.W. C. 51,000). 3. No inter‐allelic or intra‐allelic differences in molecular size were detected. 4. The estimated molecular size for rabbit muscle PGM by the same method is similar to that obtained for the human PGM1 isozymes. This is somewhat lower than previously reported estimates obtained by ultra centrifugation.