[Molecular forms of acid proteinases of the brain]

Molecular forms of cathepsin D bound with subcellular structures were studied in the grey matter of the large hemispheres. Free and bound forms of the enzymes exposed to solubilization with detergent triton X-100 were fractionated by passage through a Sephadex G-100 column. Gel chromatographic analysis demonstrated three peaks of acid proteinase activity. Different areas of solubilization curves of acid proteinases corresponded to different molecular forms of cathepsins. The initial S-shape areas of solubilization curve corresponded to the first high molecular weight peak of the enzyme activity in the grey matter, whereas the subsequent linear ones -- to the second peak; the activity of free forms of the enzyme corresponded to the third peak.