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

Cell-free extracts of a strain of Proteus vulgaris degrade NADH to reduced nicotinamide riboside, adenosine and two molecules of phosphate. The system is weakly active in fresh cell extracts, but activity is increased about 10-fold on rapid heating to 70-100 degrees C. On returning to room temperature, the activity returns rapidly to its initial low value but can be re-activated by again heating to 70-100 degrees C. Reversible activation can also be effected by extremes of pH or by teatment with 8M-urea. Activation appears to be due to reversible changes in conformation of the protein of the enzyme rather than to combination of the enzyme with a heat-labile inhibitor. The active form can be stabilized by addition of PPi. The system, which also possesses 5'-nucleotidase activity not separable from the NADH pyrophosphatase, requires Co2+ (0.4mM) for maximum activity. Although activated at relatively high temperatures, it is not enzymically active until cooled to 50-60 degrees C. It may be purified by affinity chromatography (with NAD+ as ligand) to an activity over 400 times that of the crude cell extract, and yields only one major band on polyacrylamide-gel electrophoresis.
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PMID:An enzyme degrading reduced nicotinamide-adenine dinucleotide in Proteus vulgaris. 21 47

The subcellular distribution in rat liver of non-latent and latent NADH pyrophosphatase was determined by analytical sucrose density gradient centrifugation. Non-latent NADH pyrophosphatase activity was distributed similarly to the plasma membrane marker, 5'-nucleotidase. However, latent NADH pyrophosphatase was found at the low density region of the gradient, similar to the distribution of galactosyl transferase, a Golgi marker. A population of membranes, corresponding to those from the low density region, was prepared by discontinuous sucrose gradient centrifugation. Radiolabelled insulin was used, to monitor the involvement of these membranes in ligand internalization. The membrane perturbant, digitonin, was used to effect a partial separation between membranes bearing NADH pyrophosphatase and those bearing galactosyl transferase. The mechanism by which this separation is effected has been investigated and it was shown that, although digitonin caused a loss of enzyme latency, the density shift was not due to this effect. The partially purified ligandosome-rich fraction was characterized by enzymic and ultrastructural analysis. A novel EM cytochemical stain for NADH pyrophosphatase identified a vesicular fraction distinct from Golgi lamellae.
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PMID:Isolation and partial characterization of the rat liver ligandosome fraction. 614 45