Abstract
To find the primary sequence of Irpex lacteus aspartic proteinase (ILAP), a cDNA library of I. lacteus mRNA in pBR322 was constructed. A clone, which had an insert size of about 1.2 kilobase pairs, was found to contain the coding region of the mature enzyme. The deduced amino acid sequence showed that the enzyme consisted of 340 amino acid residues with a molecular weight of 35, 000. Cysteine and methionine were not found in the enzyme and two putative N-glycosylation sites were indicated. The lack of S-S bridges in the molecule is a striking feature of the enzyme. The alignment of the sequence of the enzyme against other aspartic proteinases revealed homology around the active site aspartic acid residues.
