糸状菌によるゲンチオビオースの分解(第2報)

伊賀上 郁夫, 上原子 忠則, 鬼頭 淑芳, 倉沢 文夫

doi:10.1271/nogeikagaku1924.43.224

書誌事項

タイトル別名

Fungal Enzymes Active in Degrading Gentiobiose Part II
Aspergillus japonicus SAITO ベータ-グルコシダーゼノセイシツトゲンチオビオースニタイスルスイカイ , テンイサヨウ
Aspergillus japonicus SAITO ベータ-グルコシダーゼノセイセイトセイシツ
Some Properties of β-Glucosidase of Aspergillus japonicus SAITO and its Hydrolytic and Transfer Actions on Gentiobiose
Aspergillus japonicus SAITO β-グルコシダーゼの性質とゲンチオビオースに対する水解,転移作用

公開日: 1969

DOI

10.1271/nogeikagaku1924.43.232
10.1271/nogeikagaku1924.43.224

公開者: 公益社団法人日本農芸化学会

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説明

Kinetics of gentiobiase activity as a function of temperature, the effects of inhibitor and the mode of action were investigated using the purified β-glucosidase preparation from the bran cultures of Aspergillus japonicus SAITO. The temperature coefficient of gentiobiase reaction between 2 to 40°C was about 2.2 with the apparent activation energy of 14, 300 cal/mole. The rate of heat inactivation is characterized by the apparent activation energies of 20, 400 cal/mole below, and 53, 300 cal/mole above the critical temperature of about 68°C. The enzyme reaction was remarkably inhibited by MnO₄^- and heavy metals, such as Cu²⁺, and Hg²⁺ and Ag⁺; but Mn²⁺, Zn²⁺, Co⁺, Fe²⁺ and Fe³⁺ were less inhibitory. Molybdate and o-phenanthroline were to some degree activatory. Sulfhydryl reagents were not effective. The enzyme action on gentiobiose of various concentrations ranging from 0.25 to 10% were examined by the chromatographic technique. At higher concentrations of the sugar, transfer action in addition to hydrolytic action, was recognized and oligosaccharides of gentiobiose series, mainly gentiotriose and small amounts of 6²-β-glucosyl-cellobiose, cellobiose, and laminaribiose were detected. On the other hand, the increases of enzyme concentration or reaction time, even in the case that the gentiobiose concentrations were higher, resulted in reduction or disappearance of these reversion products. With a mixture of gentiobiose and glucose, no reversion products were detected, even in higher concentrations of gentiobiose. The action on glucose of various concentrations ranging from 2.5 to 50% resulted in the formation of reversion products with the increase in concentration of glucose. At 5% and over, gentiobiose was mainly recognized, while after a long incubation, gentiotriose was also detected in addition to gentiobiose, but no other oligosaccharides were observed. The equilibrium between glucose and gentiobiose was investigated using glucose as a substrate. The equilibrium constant was 2.19×10^-2 at 10% of glucose and 4.3×10^-2 at 20%.

収録刊行物

日本農芸化学会誌

日本農芸化学会誌 43 (4), 232-239, 1969

公益社団法人日本農芸化学会

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