A themostable intracellular β-galactosidase from a thermophilic Bacillus stearothermophilus was purified by a combination of (NH4)2SO4 fractionation, ion-exchange (DEAE-22)and gel filtration (Sephades G-75). The optimum temperature and pH of the enzyme acivity were 60Cand pH6.4 respectively. The β-galatosidase activity exhibited thermosttability at 50 C. The enzyme was significaantly activated by alkali and alkali-earth metal ions. The activity was inhibited by Zn2+ 、 Fe3+ 、 Cu2+Reducing agents enhanced β- galactosidase activity. Thiol-binding agents drastically decreased the enzyme activity. The enzyme was specific for β-D glycosidic linkages,and the identity of the aglycone moiety also influenced enzyme activity. At 55Cthe Km for O-nitrophenyl-β-D-galactosidase (ONPG)and lactose were 2. 63mmol/L and 4.39mmol/L, respectively,and Vmax for both substrates were 1.93 × 10-5mmol. min-1 mg-1protein6.54 ×105 mmol. min-1. mg-1protein,respectively. The enzyme was inhibited by glucose (the products of lactose hydrolysis,ki 2.47mmol/L),but not by galactose. In addition,the enzyme possessed transgalactosylation activity. Galacto-oligosaccharides,both tri- and tetrasaccharide,were involved in the products during lactose hydrolysi

A themostable intracellular ? galactosidase from a thermophilic Bacillus stearothermophilus was purified by a combination of (NH 4) 2SO 4 fractionation,ion exchange (DEAE 22)and gel filtration (Sephades G 75).The optimum temperature and pH of the enzyme acivity were 60℃and pH6.4 respectively.The ? galatosidase activity exhibited thermosttability at 50 ℃.The enzyme was significaantly activated by alkali and alkali earth metal ions.The activity was inhibited by Zn 2+ 、 Fe 3+ 、 Cu 2+ Reducing agents enhanced ? galactosidase activity.Thiol binding agents drastically decreased the enzyme activity.The enzyme was specific for ? D glycosidic linkages,and the identity of the aglycone moiety also influenced enzyme activity.At 55℃the Km for O nitrophenyl ? D galactosidase(ONPG)and lactose were 2.63mmol/L and 4.39mmol/L, respectively,and Vmax for both substrates were 1.93?10 5 mmol.min 1 .mg 1 protein6.54?10 5 mmol.min 1 .mg 1 protein,respectively.The enzyme was inhibited by glucose (the products of lactose hydrolysis,ki 2.47mmol/L),but not by galactose.In addition,the enzyme possessed transgalactosylation activity.Galacto oligosaccharides,both tri and tetrasaccharide,were involved in the products during lactose hydrolysis.

Objective To investigate the diagnostic value of High-Sensitive Troponin T(hs-TnT)in acute myocardial infarction(AMI). Methods One hundred and sixty nine patients with serum hs-TnT concentration≥0.014 μg/L in early hospitalization were enrolled in this study.The ROC curve was used to compare the concentra-tion of hs-TnT with four heart enzyme(CK,CK-MB,LDH,AST)on the diagnostic efficacy to AMI. The differ-ence of hs-TnT in different clinical data groups were investigated using Mann-Whitney U rank test.Then the correla-tion between hs-TnT and Gensini score of Coronary angiography was investigated using the Spearman rank correla-tion test.Results The concentration of hs-TnT in patients with chest pain was significantly higher than that in non-AMI group(P<0.05).The AUC of each ROC curve was hs-TnT(0.806)>CK-MB(0.792)>CK(0.780)>AST (0.704)> LDH(0.684). The optimal diagnostic point of hs-TnT was 0.152 ug/L(sensitivity 0.659,specificity 0.894,Yuden index 0.553).There was a positive correlation between hs-TnT and Gensini scores in men,age>65 years old and the chest tightness group(P < 0.05). Conclusion The hs-TnT is better than four heart enzyme in early diagnosis of AMI and benefit early treatment of AMI.