Action of α-amylase preparations and some proteases on the surface of mammalian erythrocytes

Abstract

Certain α-amylase preparations have been shown to possess proteolytic activity and also to release neuraminomucopeptides from bovine and rat red blood cells. This release of sialomucopeptides is accompanied by a marked decrease in the electrophoretic mobility of rat red blood cells, but not of the bovine erythrocytes. Treatment of human erythrocytes with the α-amylase preparations produces neither the release of neuraminomucopeptides nor a change in electrophoretic mobility. Treatment of the α-amylase preparations with fluoro-di-isopropyl phosphate (DFP) leads to the disappearance of proteolytic activity in the preparations from human saliva, hog pancreas, and Aspergillus oryzae, and marked inhibition of such activity in the Bacillussubtilis preparations. The DFP-treated preparations, although still possessing unimpaired α-amylase activity, produced little or no change in the electrophoretic mobility of rat red blood cells nor the release of more than traces of neuraminomucopeptides. It is concluded that the reported action of the α-amylases on the surfaces of mammalian red blood cells arises from the presence of contaminating proteolytic enzymes and not from the α-amylases per se. Some of the effects of pronase and a new proteolytic enzyme agavain on the surfaces of bovine, human, and rat erythrocytes are also reported. The results are discussed in relation to the molecular structure of the peripheral region of mammalian blood cells.