[Native and artificial sub-forms of cytoplasmic aspartate transaminase from swine heart]

Multiple forms of aspartate transaminase from cytosol of pig heart (alpha, beta and psi) were incubated in 0.05 M acetate buffer, pH 5.0 at 4 degrees within 5 and 8 months. Gradual accumulation of denaturated forms was observed on incubation of alpha- and beta-forms; these forms possessed higher mobility in polyacrylamide gel disc electrophoresis and decreased enzymatic activity as compared with the native forms. Multiple forms, produced during ageing of alpha-form, were separated by chromatography on CM-cellulose. Chromatographic resolution of the forms, their activity and spectral properties suggest that they are not identical with the native isoenzymes found in the cell.