Glycyl-L-leucinehydrolase consisting of three molecular units was extracted from C. immitis solid cultural medium. During fractionation in polyacrylamide gel of the enzyme-containing extract a 50-fold purification of the enzyme isoform with molecular weight 12,800 is achieved. The enzyme is heat-stable, active in the narrow pH range and hydrolizes peptide bonds containing glycine. Its activity is not inhibited by none of the protease inhibitors tested.