[Analysis of acid proteinases from Aspergillus terricola].

The specific action and composition of the functional groups of active centres of three fractions of acid proteinases from Aspergillus terricola have been studied. With respect to the hydrolysis rates of acetyl-L-phenylalanyl-L-tyrosine and carbobenzoxy-D, L-glycyl-phenylalanine by the three fractions it is suggested that the interaction of acid proteinases with the substrate involves hydrophobic forces. It has been shown that the above fractions are no metal enzymes. By means of the diazocarbonyl inhibitor an occurrence of a catalytically active carboxy group has been found in the active centre of proteinases. The proteinase inhibition by Fe3+ in the presence of citric acid is an indirect evidence of the existence of several carboxy groups and, possibly, of a hydroxy group in the active centre of acid proteinases from Aspergillus terricola.