Purification and characterisation of two endoglucanases from Arthrobotrys oligospora
Kumble, K.D.; Trivedi, P.N.; Jaffar, M.B.
Indian Journal of Biochemistry and Biophysics 27(3): 146-150
1990
ISSN/ISBN: 0301-1208 PMID: 2387598 Document Number: 352983
Two endoglucanases, designated Endo I and Endo II, were purified from the culture filtrates of a nematode trapping fungus, A. oligospora. The purification procedure entailed ammonium sulphate precipitation, gel filtration and preparative PAGE. Both the preparations (Endo I and Endo II) were homogeneous by PAGE, had molecular weights of 24,300 and 44,500 respectively as determined by non-denaturing PAGE, and yielded only cellobiose as the main product of CM-cellulose hydrolysis. The optimum pH and temperature for Endo I were 6.0 and 50.degree. C, and for Endo II, pH 5.6-6.4 and 50.degree. C. The two enzymes differed with respect to their Km (Endo I, 5.04 mg/ml; Endo II, 3.2 mg/ml) and energy of activation values (Endo I, 10.7 kCal; Endo II, 9.5 kCal). Both enzymes were completely inhibited by 1.25 mM Hg2+ and partially by Pb2+, DTNB and p-HMB while DTT and GSH enhanced their activities.