Primary structure of the active site region of fungal cutinase, an enzyme involved in phytopathogenesis.

Cutinase, a fungal extracellular enzyme involved in phytopathogenesis, was labeled by treatment with [3H]diisopropylfluorophosphate and by reduction of the only disulphide with dithioerythritol followed by treatment with iodo[1-14C]acetamide. A tryptic peptide containing both the active serine and one of the cys involved in the disulphide bridge was isolated and the primary structure was determined to be: Glu-Met-Leu-Gly-Leu-Phe-Gln-Gln-Ala-Asn-Thr-Lys-Cys-Pro-Asp-Ala-Thr-Leu-Ile-Ala - Gly-Gly-Tyr-Ser-Gln-Gly-(Ala)-Ala-Leu-Ala. This active site has very little homology with the active serine containing regions of other enzymes.