β-N-Acetyl-D-glucosaminidase （NAGase, EC.3.2.1.52） is chitinolytic enzymes and disintegrate dimmer and trimer a composition of oligomers of N-acetyl-β-D-glucosamine （NAG） into monomer. Prawn （P. vannamei） NAG...β-N-Acetyl-D-glucosaminidase （NAGase, EC.3.2.1.52） is chitinolytic enzymes and disintegrate dimmer and trimer a composition of oligomers of N-acetyl-β-D-glucosamine （NAG） into monomer. Prawn （P. vannamei） NAGase is involved in digestion and molting processes. Some pollutants in seawater affect the enzyme activity causing loss of the biological function of the enzyme, which affects the exuviating shell and threatens the survival of the animal. The effect of formaldehyde on prawn （P. vannamei） β-N-acetyl-D-glucosaminidase activity for the hydrolysis of pNP-NAG has been studied. The results show that formaldehyde, at appropriate concentrations, can lead to reversible inactivation of the enzyme, and the IC50 is estimated to be 1.05mol· L^-1. The inactivation mechanism obtained from Lineweaver-Burk plots shows that the inactivation of the enzyme by formaldehyde belongs to the competitive type. The inactivation kinetics of the enzyme by formaldehyde has been studied using the progress-of-substrate-reaction method described by Tsou, and the rate constants have been determined. The results show that k＋0 is much larger than k-0, indicating the free enzyme molecule is fragile in the formaldehyde solution.展开更多
Objective. The goal of this paper is to investigate the relationship between the N-glycosylation of acetylglucosaminyltransferase V(Glc NAcT-V) and its activity and to know which site among the 6 N-glycosylation sites...Objective. The goal of this paper is to investigate the relationship between the N-glycosylation of acetylglucosaminyltransferase V(Glc NAcT-V) and its activity and to know which site among the 6 N-glycosylation sites in the GlcNAcT-V gene is the most important. Methods.Wild type of GlcNAcTV was transfected into COS7 cells and its activity was measured 48 h later. The first site (Asn 110) was mutated with sitedirected mutagenesis and transfected into COS7 cells. Results. It was found that after the cells were added tunicamycin(TM, 1 μ g/ml), the activity was 117% of the wild type. The activity of the cells with mutating GlcNAcTV was about 120% of the wild type RTPCR showed that there was no significant change in mRNA expression among the three groups. Conclusion.The Nglycosylation is important for its activity. Our results suggest that the Nlinked carbohydrates on GlcNAcTV are required for the posttranscriptional activity of the enzyme.展开更多
OBJECTIVE: To investigate changes in renal function, urine N-acetyl-beta-D-glucosaminidase enzyme (N-AG),liver function, myocardial enzymes, the pathology of renal damage and the mechanism of acute renal failure (ARF)...OBJECTIVE: To investigate changes in renal function, urine N-acetyl-beta-D-glucosaminidase enzyme (N-AG),liver function, myocardial enzymes, the pathology of renal damage and the mechanism of acute renal failure (ARF) associated with fish gall bladder poisoning. METHODS: Eleven patients with acute fish gall bladder poisoning were consecutively admitted to our hospital from September 1997 to October 1999. Renal function, urine N-AG enzyme, liver function, and myocardial enzymes were assayed before and after treatment. One patient consented to a kidney biopsy and the pathology of renal damage was observed under light and electron microscopes. RESULTS: All patients had multiple organ dysfunction syndrome (MODS) and 11 patients suffered from ARF. Ten patients had liver dysfunction, ten patients had poisonous myocarditis, and 8 patients had gastrointestinal dysfunction. Renal function, urine N-AG enzyme, liver function, and myocardial enzymes were significantly improved after treatment compared with those of before treatment (P展开更多
文摘β-N-Acetyl-D-glucosaminidase （NAGase, EC.3.2.1.52） is chitinolytic enzymes and disintegrate dimmer and trimer a composition of oligomers of N-acetyl-β-D-glucosamine （NAG） into monomer. Prawn （P. vannamei） NAGase is involved in digestion and molting processes. Some pollutants in seawater affect the enzyme activity causing loss of the biological function of the enzyme, which affects the exuviating shell and threatens the survival of the animal. The effect of formaldehyde on prawn （P. vannamei） β-N-acetyl-D-glucosaminidase activity for the hydrolysis of pNP-NAG has been studied. The results show that formaldehyde, at appropriate concentrations, can lead to reversible inactivation of the enzyme, and the IC50 is estimated to be 1.05mol· L^-1. The inactivation mechanism obtained from Lineweaver-Burk plots shows that the inactivation of the enzyme by formaldehyde belongs to the competitive type. The inactivation kinetics of the enzyme by formaldehyde has been studied using the progress-of-substrate-reaction method described by Tsou, and the rate constants have been determined. The results show that k＋0 is much larger than k-0, indicating the free enzyme molecule is fragile in the formaldehyde solution.
文摘Objective. The goal of this paper is to investigate the relationship between the N-glycosylation of acetylglucosaminyltransferase V(Glc NAcT-V) and its activity and to know which site among the 6 N-glycosylation sites in the GlcNAcT-V gene is the most important. Methods.Wild type of GlcNAcTV was transfected into COS7 cells and its activity was measured 48 h later. The first site (Asn 110) was mutated with sitedirected mutagenesis and transfected into COS7 cells. Results. It was found that after the cells were added tunicamycin(TM, 1 μ g/ml), the activity was 117% of the wild type. The activity of the cells with mutating GlcNAcTV was about 120% of the wild type RTPCR showed that there was no significant change in mRNA expression among the three groups. Conclusion.The Nglycosylation is important for its activity. Our results suggest that the Nlinked carbohydrates on GlcNAcTV are required for the posttranscriptional activity of the enzyme.
基金ThisworkwassupportedbyagrantfromtheMedicalScienceFoundationofHunanHealthAdministration (No 983 2 9)
文摘OBJECTIVE: To investigate changes in renal function, urine N-acetyl-beta-D-glucosaminidase enzyme (N-AG),liver function, myocardial enzymes, the pathology of renal damage and the mechanism of acute renal failure (ARF) associated with fish gall bladder poisoning. METHODS: Eleven patients with acute fish gall bladder poisoning were consecutively admitted to our hospital from September 1997 to October 1999. Renal function, urine N-AG enzyme, liver function, and myocardial enzymes were assayed before and after treatment. One patient consented to a kidney biopsy and the pathology of renal damage was observed under light and electron microscopes. RESULTS: All patients had multiple organ dysfunction syndrome (MODS) and 11 patients suffered from ARF. Ten patients had liver dysfunction, ten patients had poisonous myocarditis, and 8 patients had gastrointestinal dysfunction. Renal function, urine N-AG enzyme, liver function, and myocardial enzymes were significantly improved after treatment compared with those of before treatment (P
