Biopolymers and cell. 2000; 16 (6): 487 - 494

Properties of high-molecular-mass ATP-dependent proteinase from the erythroid cells of piglets

H. L. Antony ok

The present article reports the characterization of high-molecular-mass ATP-dependent proteinase from the erythroid ceils of neonatal piglets. The enzyme was purified by DEAE-Toyopearl 650M, Toyopearl HW-55 gel filtration and hydroxyapatite chromato-graphies. The molecular mass of enzyme has been found to be 700±50 kDa by gel filtration, the optimum activity was observed at around pH 8.5. The enzyme hydrolysed synthetic substrate Suc-Leu-Leu-Val-Tyr-MCA and showed proteolytic activity towards casein and several o ther proteins in the presence of ATP. The degradation of the protein substrates was stimulated by 0.05 % sodium dodecyl sulfate and linoleic acid. The casein-hydrolyzing activity decreased in the presence of phenylmethylsulfonylfluoride and n-chloromer-curibenzoic acid. T he enzyme activity reached high levels in the proliferating erythroblasts of animal bone marrow and decreased as the cells matured. The high levels of the proteinase activity were observed in the erythroid cells of newborn piglets, whereas in the cells of JO-days-old animals the enzyme activity was significantly lower. A role of ATP-dependent high-molecular-mass proteinase in functional activity of animal erythroid cells in the neonatal period discussed.