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)

We have perfused isolated rat livers with hypocalcemic (4.4 mg 100 ml) Krebs-Ringer bicarbonate albumin buffer. After 15 min of perfusion, a substance appeared in the perfusate which decreased rat renal adenylate cyclase activation by parathyroid hormone (PTH). The material in the perfusate was purified greater than 50,000-fold by Bio-Gel P-10 chromatography. The purified antagonist decreased the activation of rat renal cortical adenylate cyclase by PTH, glucagon, and epinephrine 75 to 100%. Concentration response curves for each of the hormones indicated a noncompetitive interaction of the inhibitor with the hormone. The inhibition was not species-specific, as the activation of the parathyroid hormone-responsive adenylate cyclase in cat renal cortex was also abolished by the inhibitor from the perfused rat liver. The inhibitor is a peptide, Mr equal to similar to 1000, which is heat-stable, acid-stable, alkai-labile, and is destroyed by trypsin, leucine aminopeptidase, and elastase. It is not destroyed by phosphodiesterase, 5'-nucleotidase, alkaline phosphatase, neuraminidase, RNase, or phospholipase A. The inhibitor is not produced by isolated rat livers perfused with normocalcemic perfusion media. It is unclear whether the peptide is synthesized by the liver or whether it is a breakdown product of a larger peptide or protein in the liver. This is the first reported peptide inhibitor of adenylate cyclase.
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PMID:Isolation of a unique peptide inhibitor of hormone-responsive adenylate cyclase. 16 24

A comparative study of glucose-6-phosphatase, alcaline RNase, ATPase, inosine diphosphatase and 5'-nucleotidase activities in isolated rat liver and hepatoma-27 nuclei and nuclear envelopes was performed. The tumor nuclear membranes were shown to be free from G-6-Pase activity in contrast to the liver nuclear membranes. The nuclear RNase activity was strongly inhibited in the hepatoma and could be unmasked in the presence of 3-10(-4) M pCMB. Hepatoma nuclear and nuclear envelopes ATP-ase activity was found to be moderately decreased as compared to those of the normal tissue. The values of inosine diphosphatase activity in hepatoma were similar to those in liver. The role of the nuclear envelope in nuclear-cytoplasmic interactions as well as nuclear location of G-6-Pase are discussed.
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PMID:[Various enzymes of isolated nuclear membranes and cell nuclei of the liver and hepatoma 27 of rats]. 19 29

Estimates for the overall protein content of the periplasm of Escherichia coli range from 4 to 16% of cellular protein. A cursory examination of known sources of contamination inherent to the methods employed for measurement leads to the conclusion that even the lower value may represent an overestimate of the periplasmic protein in E. coli. The protoplast supernatant fraction (PSF) of Bacillus subtilis defines operationally a potential periplasm, which, after correction for cytoplasmic contamination, yielded, in B. subtilis strains 168 and W23, calculated values of 9 and 3%, respectively, of cell protein as being periplasmic. 26 Among enzymes typically periplasmic in E. coli, at least two, RNases and a 5'-nucleotidase, were located in the B. subtilis periplasm. Compared to other cell fractions, RNase activity in the periplasm was associated with several protein bands forming a unique profile. Samples from all growth phases of cells cultured under phosphate-limitation and phosphate-excess revealed that a major part of both investigated activities was induced by phosphate depletion and located outside the plasma membrane. The current belief that a periplasm containing soluble enzymes does not exist in gram-positive bacteria is examined in light of the absence of an outer membrane permeability barrier, and of a clearly defined electron-transparent zone located between the plasma membrane and the cell wall of B. subtilis. Previous results of studies of protein secretion, and cell wall permeability, are reinterpreted by assuming that the thick charged cell wall of gram-positive bacteria can act as the outer permeability barrier, and as such be the functional equivalent of the outer membrane of gram-negative organisms.
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PMID:Overall protein content and induced enzyme components of the periplasm of Bacillus subtilis. 915 17

In Scrobicularia plana testis, a nuclear acid phosphatase (ACPase) activity was detected in mid and late spermatids with the improved Gomori-chloride procedure. Lead deposits were first observed in mid spermatids at focal points over condensed chromatin strands, increasing in density as chromatin further condensated. In late spermiogenesis, lead deposits became concentrated between chromatin aggregates, and after total DNA compaction were transfered to the nuclear periphery and then shed into the cytoplasm. The specificity of the nuclear ACPase was tested against different pH values (3.9, 7.2, 7.8, 9.0), substrates (TPP, IDP, TMP, p-NCS, ATP, GTP, AMP, ADP, AMP-PNP) and inhibitors (NaF, levamisole, Zn, vanadate, theophylline). To further specify the nature of this nuclear ACPase, other enzymes were comparatively studied at their optimal pH values and at pH 5.0: nucleoside-diphosphatase, thiamin-pyrophosphatase, inorganic trimetaphosphatase, lysosomal arylsulfatases A and B, ATPase, GTPase, 5'-nucleotidase, adenylate kinase, and adenylate cyclase. Several other controls were introduced to exclude artefactual deposits induced by lead ions and tissue molecules. The results showed that the enzyme has an optimal pH at 5.0, a high specific affinity for beta-GP, and is inhibited by NaF, which suggests that it behaves as a type B-ACPase, and all controls demonstrated the specificity of the enzymic activity. Because lead deposits were specifically and temporally associated with spermatid chromatin condensation, when DNA and RNA synthesis, histones, phosphoproteins and RNA molecules strongly decrease, it is possible to suggest that the nuclear ACPase could be associated with DNA processing during chromatin compaction or involved in the hydrolysis of 2' and 3' nucleotides resulting from nuclear RNase action during RNA degradation.
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PMID:Chromatin condensation during Scrobicularia plana spermiogenesis: a controlled and comparative enzymatic ultracytochemical study. 1079 22

We report here the presence in human milk fat globules membranes of 5'-nucleotidase, Na(+)-K(+) and Mg(2+) ATPases, and phosphodiesterase which are marker enzymes for the plasma membrane. Thiamine-pyrophosphatase, lactose and lactosamine synthetase were also found, which are usually considered as Golgi apparatus marker enzymes. Lastly, glucose-6-phosphatase, NADH-cytochrome c reductase and RNase, characteristic enzymes of the endoplasmic membrane, were also present.
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PMID:??? 1194 14