Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe a bioluminescence method for measuring adenosine deaminase activity in serum. The method involves use of batchwise enzyme reaction containing adenosine, alpha-ketoglutarate, glutamic dehydrogenase and NADH. The resulting solution is injected to the continuous-flow bioluminescence system. In the system, a bacterial luciferase and NAD(P)H:FMN oxidoreductase are covalently co-immobilized on Sepharose 4B. Carrier solution (pH 6.8) for bioluminescence reaction contains FMN and decanal. The continuous-flow light-emitting system, in which the reactor (flow cell packed with immobilized enzyme) is placed in front of a photomultiplier tube inside a photon counter, is versatile and simple. Concentration and response are linearly related from 1.2 to 92.5 pmol per injection of ammonia. The precision of the method is satisfactory (coefficient of variation 3.9-6.8%). We validated the technique by comparing results with conventional assay method (UV method). Normal values for adenosine deaminase activity of serum ranged from 7.0 to 22.0 U/l in agreement with those obtained by other method. The Sepharose 4B-immobilized enzymes are stable for more than one year. This assay system could be used as a routine clinical laboratory test in the diagnosis of liver damage.
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PMID:Bioluminescent assay for serum adenosine deaminase with immobilized bacterial luciferase. 262 Apr 50

An assay of adenosine deaminase activity in pleural effusions is described. For the continuous determination of adenosine deaminase, the liberated ammonia is estimated by coupling the liberated NH3 with 2-oxoglutarate. The reaction is followed by the decrease of NADH absorbance at 340 nm. The assay was optimized for a Hitachi 705 analyser, with respect to pH, adenosine concentration and glutamate dehydrogenase activity. The assay is linear to an adenosine deaminase catalytic concentration of 110 U/l. Elevated adenosine deaminase activities are found in pleural effusions of patients with tuberculosis, empyema and mesothelioma. Although elevated adenosine deaminase activity in pleural effusion is not pathognomonic for tuberculosis, it may be valuable as a first screening parameter.
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PMID:A continuous method for the estimation of adenosine deaminase catalytic concentration in pleural effusions with a Hitachi 705 discrete analyser. 406 16

1. Tubule fragments were isolated from renal cortex of fed rats. 2. Gluconeogenesis from lactate was significantly increased by low concentrations of exogenous ATP, ADP, AMP adenylyl (beta, gamma-methylene)diphosphonate and, to a lesser extent, by ITP and inosine. GTP was slightly inhibitory. Hypoxanthine was ineffective. Exogenous adenosine deaminase slightly decreased gluconeogenesis and was additive in effect to GTP. Adenosine deaminase did not abolish the stimulatory effects of ATP or cyclic AMP. 3. 40 microM ATP also stimulated gluconeogenesis from pyruvate, malate, succinate, 2-oxoglutarate and glutamine, but had no effect when glycerol or fructose were used as substrates. 4. With lactate as substrate the effect of 40 microM ATP was additive to the maximal stimulations of gluconeogenesis seen with 1 microM noradrenalin or 0.1 microM angiotensin II, but was not additive to the stimulatory effect of 0.1 mM cyclic AMP. 5.40 microM ATP had no effect upon either the tubule content of cyclic AMP or upon 45Ca efflux from prelabelled tubules. 6. Addition of ouabain or removal of extracellular K+ diminished the stimulatory effects of ATP and cyclic AMP. 7. Extracellular ATP was rapidly metabolized by tubule fragments, with resulting accumulation of adenosine. Further metabolism resulting in formation of inosine, hypoxanthine, xanthine and uric acid was also observed. Cyclic AMP was metabolized less rapidly, with no accumulation of adenosine. 8. The effects of purinergic agents on gluconeogenesis are discussed.
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PMID:Stimulation of renal gluconeogenesis by exogenous adenine nucleotides. 629 8

KW-3902 (8-(noradamantan-3-yl)-1,3-dipropylxanthine) is a novel potent and selective adenosine A(1) receptor antagonist. We examined the effect of KW-3902 on p-aminohippurate (PAH) transport in opossum kidney (OK) epithelial cells. Pretreatment for 3 h with KW-3902 inhibited the transcellular transport of PAH across OK cell monolayers from the basal to the apical side. The uptake of PAH across the basolateral membrane of OK cells was inhibited by KW-3902 pretreatment in a time- and concentration-dependent manner. A kinetic analysis revealed that the inhibitory effect of KW-3902 on the basolateral PAH uptake was due to an increase in the Michaelis constant (K(m)) as well as a decrease in the maximum uptake rate (V(max)), showing that the inhibition was a mixed type. Pretreatment with adenosine deaminase or 8-cyclopentyl-1,3-dipropylxanthine, another selective adenosine A(1) receptor antagonist, also decreased the basolateral PAH uptake. KW-3902 pretreatment had no effect on the concentration of intracellular alpha-ketoglutarate which exchanges for PAH across the basolateral membrane of OK cells. These results suggest that KW-3902 has an inhibitory effect on PAH transport in OK epithelial cells.
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PMID:Inhibitory effect of KW-3902, an adenosine A(1) receptor antagonist, on p-aminohippurate transport in OK cells. 1040 68