Cryoinactivation and conformational drift of glyceraldehyde-3-phosphate dehydrogenase from rabbit muscle

The cryoinactivation of glyceraldehyde-3-phosphate dehydrogenase from rabbi t muscle (GAPDH-rabbit) was studied. It was found that the inactivation of GAPDH-rabbit at 0 degrees C was much faster than that of GAPDH from yeasts, and showed obvious time and concentration dependence. The spectral propert ies, enzyme activity and behavior under pressure, of GAPDH-rabbit treated e ither by cryoinactivation, or pressure-induced dissociation and reassociati on, were very similar. These results provided evidence to support the idea that cryoinactivation of oligomeric proteins, might take place through a cy cle of dissociation-reassociation accompanied with the so-called conformati onal drift postulated by King and Weber (1986).