Yeast aldehyde dehydrogenase. IV. Dissociation and reassociation of native and hybrid forms.

Yeast aldehyde dehydrogenase and each of two of its active proteolytic digestion products are readily dissociable into subunits which can, in turn, reassociate. The native protein dissociates into four subunits of equal sire. The partially digested enzymes dissociate into the same subunit plus a second, smaller subunit. The data are interpreted in terms of a tetrameric native enzyme, differing from its tetrameric degradation products, of which four are known, in the number of intact and functional subunits. Dissociation and reassociation of one of the hybrid forms resulted in the formation principally of a catalytically active aldehyde dehydrogenase, indistinguishable from the native enzyme.