CMC-LIQUEFYING ENZYME, A LOW-MOLECULAR-MASS INITIAL CELLULOSE-DECOMPOSING CELLULASE RESPONSIBLE FOR FRAGMENTATION FROM STREPTOMYCES SP LX

Streptomyces sp. LX, newly isolated from soil, was shown to secrete a carboxylmethylcellulose (CMC)-liquefying enzyme that cleaves the CMC c hains, releasing negligible reducing terminals. The new enzyme, named component C-2, was purified to homogeneity by dialysation. It has a mo lecular mass of 9.8 kDa. The pH optimum of the enzyme activity is 6.4 and its temperature optimum is 50 degrees C. It retains full activity at pH 4-6.4 upon incubation at 50 degrees C for 30 min. The enzyme has significant fragmentation activity on filter paper despite the absenc e of weight loss, release of reducing sugars and depolymerization duri ng incubation with filter paper. The one-electron oxidative reaction i s shown not to participate in the fragmentation of filter paper by enz yme C-2.