An α-L-Arabinofuranosidase from Streptomyces purpurascens IFO 3389

Abstract

By screening 46 strains of Actinomycetes for their ability to hydrolyze arabinan, 16 strains were found to have α-L-arabinofuranosidase activity, and Streptomyces purpurascens IFO 3389 was selected as the most promising of the sixteen. An α-L-arabinofuranosidase [EC 3.2.1.55] has been highly purified from the culture fluid of this organism grown on beet arabinan as the carbon source. The molecular weight of the native enzyme was determined to be 495, 000 by gel filtration and that of the subunit to be 62,000 by SDS polyacrylamide gel electrophoresis. The pI value was 3.9. The purified enzyme was active on p-nitrophenyl α-L-arabinofuranoside and arabino-oligomers, and inactive on arabinan, arabinoxylan and arabinogalactan. The optimum pH was 6.5. The enzyme was inhibited by Hg2+, Ag+and L-arabino-γ-lactone. The values of Km and Vmaxfor p-nitrophenyl α-L-arabinofuranoside were determined to be 8.2 x 10-5m and 89.3 μmol per min per mg of protein, respectively. © 1982, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.