title: Purification and some properties of a starch debranching enzyme ofHendersonula toruloidea.
abstract: An extracellular, debranching isoamylase fromHendersonula toruloidea ATCC 64930, grown on starch, was purified 12-fold to an electrophoretically homogeneous state. The purified enzyme (estimated mol wt 83000) was optimally active at pH 6.0 and 50°C and remained active when held at 70°C (30 min) and at pH 6 to 8 for 24 h. Na(+), Fe(2+) and Ba(2+) (at 5MM) enhanced enzyme activity while Hg(2+), Zn(2+) and Cu(2+) (at 5MM) were inhibitory. The enzyme hydrolysed amylopectin (Km, 0.25 mg/ml), forming maltose, maltotriose and maltotetraose and hydrolyzed glycogen (Km, 0.29 mg/ml) and soluble starch (Km, 0.42 mg/ml) forming maltotriose and maltotetraose. Pullulan was not hydrolyzed.
authors.affiliation: Department of Applied Microbiology and Brewing, Anambra State University of Technology, P. M. B. 5025, Awka, Nigeria.
authors.forename: F J
authors.initials: FJ
authors.lastname: Odibo
authors.forename: N
authors.initials: N
authors.lastname: Okafor
authors.forename: M U
authors.initials: MU
authors.lastname: Tom
authors.forename: C A
authors.initials: CA
authors.lastname: Oyeka