Subunit structure and multifunctional properties of yeast phosphoglyceromutase.

1. A new and efficient method for preparation of pure phosphoglyceromutase from baker's yeast (Saccharomyces cerevisiae) is described. Proteolytic alterations of the enzyme during extraction can be minimized by grinding the dried yeast with aluminium oxide at low temperature. 2. Yeast phosphoglyceromutase contains four highly similar, probably idential subunits of molecular weight 28000, a conclusion based on the following observations. Polyacrylamide gel electrophoresis containing dodecylsulphate or urea gives a single band, indicating that the enzyme is composed of four subunits similar in their molecular weight and net charge. Cyanogen bromide cleavage and tryptic digestion of the enzyme yield the number of peptides expected for identical subunites from the amino acid composition analysis. 3. The purified phosphoglyceromutase preparation has bisphosphoglyceromutase activity synthesizing 2,3-bisphosphoglycerate from 1,3-bisphosphoglycerate and 3-phosphoglycerate. It has been reported that yeast phosphoglyceromutase catalyzes the hydrolysis of 2,3-bisphosphoglycerate at the same active site which catalyzes the phosphoglyceromutase reaction [Sasaki, R. et al (1971) Biochim. Biophys, Acta, 227, 584-594, 595-607]. Immunological studies and chemical modification experiments indicate that bisphosphoglyceromutase activity also is due to the phosphoglyceromutase protein and involves amino groups which have been shown to be essential for the other two activities.