Purification and Properties of a New endo-Cellulase from Robillarda sp. Y-20

Abstract

A cellulolytic enzyme was purified from a crude enzyme preparation from Robillarda sp. Y-20 by consecutive column chromatography. The purified enzyme was homogeneous on polyacrylamide gel electrophoresis and contained 10.5% carbohydrate as glucose. The enzyme had a molecular weight of 56,000, an isoelectric point of 3.80, an optimum pH of 5.0, and an optimum temperature of 60°C. It was stable from pH 4.0 ~ 7.0 at 37°C for 1 hr and below 50°C for 30 min.

The amino-terminal amino acid sequence of the enzyme was

The enzyme was inactivated by 1 mm Fe³⁺, Hg²⁺, or N-bromosuccinimide. It was active on sodium carboxymethyl cellulose (CMC) and cellooligosaccharides (cellotriose to cellohexaose), but not on either cellobiose or microcrystalline cellulose (Avicel) under our assay conditions. The Km value of the enzyme for CMC was 0.060%.