テラピア腸管アミラーゼの精製ならびに性状について

抄録

Amylases of the intestine of Tilapia nilotica were purified by ammonium sulfate precipitation, followed by affinity chromatography (α-cyclodextrin-Sepharose 6B), Chromatofocussing (poly-exchanger PBE 94), and gel filtration (Sephadex G-75). Two different amylases were obtained in pure state and tentatively designated AA-2 and AB-2.
The specific activity of AA-2 and AB-2 were 620- and 670-fold over the crude enzyme, respectively.
.AA-2 and AB-2 had molecular weights of 54, 000 and 56, 000, respectively, and showed the highest activity at 40°C and at a pH of 6.0. They were stable at pH 5.5-7.5 and below 45°C.
The Km values for soluble starch of the two enzymes were calculated to be 0.48mg/ml and 0.67mg/ml, respectively.
Both activities of the enzymes were inhibited by Hg²⁺, CH₂ICOOH, PCMB, and DTNB. The enzymes specifically digested soluble starch, and gave maltose, maltotriose, and maltotetraose. Wheat starch was the most digested of several raw starches examined.