Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method is described for the isolation of secondary lysosomes from homogenates of rabbit liver; The uptake of Triton WR-1339 by rabbit-liver lysosomes when administered by intraperitoneal injection was used to decrease the density of secondary lysosomes. Lysosomal fractions prepared by this method contain an NAD nucleosidase (NAD glycohydrolase, EC 3;2.25), an enzyme which has previously been considered to be associated with other subcellular fractions. The enzyme has maximum activity at pH 6 and cleaves both NAD and NADP. It is inhibited by nicotinamide (Ki equals 4.5 mM) and by HgCl2. Both nucleosidase and 2'-nucleotidase show in-vitro latency typical of lysosomal acid hydrolases. Rabbit-liver plasma-membrane fractions were isolated which contained most 5'-nucleotidase but relatively little nucleosidase, whereas rabbit liver lysosomes contain both 5'-nucleotidase and nucleosidase enzymes but little adenyl cyclase.
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PMID:Evidence for NAD nucleosidase in rabbit-liver lysosomes. 23 77

The aim of the present investigation was to evaluate the effect of a subchronic treatment (30 days/30 doses) with subcutaneous injections (0.1 mg/kg) of HgCl2 on NTPDase (E.C. 3.6.1.5), 5'-nucleotidase (E.C 3.1.3.5) and acetylcholinesterase (AChE, E.C. 3.1.1.7) activities in brain from adult rats. NTPDase and 5'-nucleotidase were measured in cortical synaptosomal fraction and AChE was measured in the homogenate of cerebral cortex and hippocampus. After the subchronic treatment (30 days), NTPDase activity was enhanced approximately 35% (p < 0.05) with ATP and ADP as substrates and no difference was observed in 5'-nucleotidase activity (AMP hydrolysis). In addition, AChE activity was enhanced in the cerebral cortex (22%, p < 0.05) and hippocampus (26%, p < 0.05) after the subchronic treatment. Mercury deposited in brain was measured by cold vapor (atomic absorption spectrometry) and no difference between the control and the subchronically treated group was observed. Here we showed for the first time that exposure to low levels of Hg2+, which resembles occupational exposure to low levels of mercury, caused a marked increase in NTPDase and AChE activities. The relationship of these alterations with the neurotoxicity of inorganic mercury deserves further studies.
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PMID:Effect of subchronic treatment with mercury chloride on NTPDase, 5'-nucleotidase and acetylcholinesterase from cerebral cortex of rats. 1513 88

The effectiveness of the antioxidant thiol, N-acetylcysteine (NAC), in enhancing methylmercury (CH3HgCl) excretion and its utility as a possible antidote in CH3HgCl poisoning has been reported. NAC, however, has been reported to be ineffective in accelerating excretion of divalent toxic metals, including inorganic mercury, Hg2+. In this study, we evaluated the possible protective effect of short-term pretreatment with NAC against mercuric chloride (HgCl2) toxicity in rat model. This is aimed at determining its chemopreventive or prophylactic benefit in situations of high risk exposure (occupational/industrial) to mercury. Rats were divided into three treatment groups. Group I received saline (10 ml/kg) and served as control. Group II received HgCl2 (5mg/kg) and group III received NAC (10mg/kg) plus (5mg/kg). All administration was via intraperitoneal (i.p.) injection. Saline and NAC were administered for 5days and HgCl2 was administered to rats in groups II and III on the 5th day. Animals were sacrificed 24 hours after HgCl2 injection and samples obtained for biochemical evaluation. Results revealed that single i.p. injection of HgCl2 induced significant renal oxidative damage resulting in significant decrease in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST), depletion of reduced glutathione (GSH) and increase in malondialdehyde (MDA) levels in these rats. The activities of glucose-6-phosphatase (G6Pase) and 5'-nucleotidase (5'-NTD) (markers of microsomal damage) also decreased in these HgCl2 treated rats. The oxidative damage induced by HgCl2 led to significant alterations in renal histology and caused functional impairment (indicated by elevated blood urea nitrogen (BUN) and serum creatinine) in these rats. NAC was effective in attenuating the oxidative damage, functional impairments and histopathological changes that characterized HgCl2 intoxication in this study. Renal antioxidant defense system was re-enforced by NAC, leading to increase in the activities of SOD, CAT, GST and decreases in GSH depletion and MDA level. Our results therefore reveal the ameliorative effect of NAC pretreatment against HgCl2 toxicity in vivo, thus, suggesting its usefulness as a possible chemoprophylactic agent during occupational or industrial exposure to inorganic mercury.
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PMID:N-acetylcysteine pretreatment ameliorates mercuric chloride-induced oxidative renal damage in rats. 2241 58