Reesei Cbh ¢ñ Synthesis Of Glycosidic Nature Discussed

By PAGE,CBHⅠ(cellobiohydrolaseⅠ) was purifed from commercial cellulase, which was extracted from Trichoderma reesei. The activity of this enzyme was researched with kinds of substrates. The hydrolytic activity of CBHⅠwas detected at 45℃pH5.5. Its Km was 5.29mg/ml, and the Vmax was 0.420ug/min with sucrose as substrate; its Km was 2.95mg/ml, and the Vmax was 0.041ug/min with 4-nitrophenyl-β-D-cellobioside (pNPC) as substrate. The quantity change of the reducing sugar in sucrose hydrolysis reaction and the p-nitrophenol in pNPC hydrolysis reaction were detected in a long time. It was demonstrated that there were absolute reversible reactions in the two close reaction systems. The periodic oscillation in the quantity change of the reducing sugar and p-nitrophenol were found, and the oscillation periods were 21.67±2.89min and 23.75±2.5min respectively.DNS method was used to analyze the quantity change of the reducing sugar when CBHⅠreacted with xylose and fructose respectively in a long time. The result showed that in the close reaction system, the reducing sugar quantity changed regularly with periodic raise and decrease, and the oscillation periods were 33.33±5.77min and 41.75±9.07min respectively. The acetylated products were deteced by GC/MS, using xylose as substrate after 5min-reaction time. It was confirmed that a kind of disaccharide existed in the reaction products, and it supported the hypothesis that Trichoderma reesei CBHⅠhad the glycoside synthesis activity to xylose.