Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

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 localization and characterization of phospholipases A1 and A2 (EC3.1.1.4) in Krebs II ascites cells, particularly in the plasma membranes. Cells were lysed with a Dounce homogenizer in an isotonic sucrose medium. Plasma membranes sediment with mitochondria and lysosomes during subcellular fractionation and are finally isolated on a continuous sucrose gradient. The membranes are localized at two levels in the gradient, at densities of 1.06 and 1.15, in which 5'-nucleotidase (EC 3.1.3.5) activity exhibits a 9- and 21-fold purification, respectively. Total contamination by endoplasmic reticulum, lysosomes, and mitochondria is 17 percent for the low-density membrane fraction and 25 percent for the high-density fraction. The phospholipases A present in Krebs II cells are active at pH 4.0 and pH 7.5. At the 2 pH values, they have A1 and A2 specificities. The intracellular distribution of acidic forms is comparable to that of acid phosphatase (EC 3.1.3.1), while neutral forms are localized like lactate dehydrogenase (EC 1.1.1.27). A small proportion of neutral phospholipase A2 has the same repartition on the sucrose gradient as nicotinamide adenine dinucleotide diaphorase (EF 1.6.4.3), an endoplasmic reticulum marker, and as 5'-nucleotidase, a plasma membrane marker.
...
PMID:Phospholipases A1 and A2 in subcellular fractions and plasma membranes of Krebs II ascites cells. 2 44

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.
...
PMID:Isolation of a unique peptide inhibitor of hormone-responsive adenylate cyclase. 16 24

1. The enzymatic, hemorrhagic, procoagulant and anticoagulant activities of venoms of some animals including snakes, lizards, toads, scorpions, spider, wasps, bees and ants were compared. 2. Snake venom was the richest source of enzymes among the animal venoms. Most other animal venoms were devoid of phosphodiesterase, L-amino acid oxidase, alkaline phosphomonoesterase and acetylcholinesterase activities and only a few exhibited arginine ester hydrolase activity. These venoms, however, exhibited wide ranges of protease, 5'-nucleotidase and hyaluronidase activities. Most of the animal venoms examined exhibited some phospholipase A activity. 3. Other than snake venoms, only venoms of the toad Bufo calamita and the lizards were hemorrhagic, and only venoms of the social wasps, social bees and harvester ant exhibited strong anticoagulant activity. Procoagulant activity occurs only in snake venoms.
...
PMID:Comparative study of the enzymatic, hemorrhagic, procoagulant and anticoagulant activities of some animal venoms. 136 Mar 87

Citrate levels in selected snake venoms were determined by an enzymatic assay coupled to NADP+ reduction. Citrate concentrations in different viper venoms (n = 5) varied from 95 to 150 mM, in crotalids (n = 3) from 63 to 142 mM, and in elapids (n = 4) from 17 to 163 mM. In Bothrops asper venom Ca(2+)-ion concentrations varied from 2.5 to 3.6 mM, suggesting that the high relative citrate levels may serve to chelate endogenous divalent metal cations, thereby inactivating divalent cation requiring enzymes. Control experiments with B. asper phospholipase A2 MIII in the presence of 2.5 mM Ca2+, showed that the enzyme is completely inhibited by 20 mM citrate. Crotalus adamanteus 5'-nucleotidase and phosphodiesterase are also inhibited 100 and 75%, respectively, by 100 mM citrate. By forming complexes with divalent metal ions, citrate markedly reduces the activities of selected enzymes in snake venoms. Secretion of high concentrations of citrate may represent an important mechanism by which snakes protect themselves against the toxic effects of their own venoms.
...
PMID:Citrate is an endogenous inhibitor of snake venom enzymes by metal-ion chelation. 144 Jun 29

1. The biological properties of nine venom samples from six taxa of Micrurus were investigated. The venoms exhibited low protease, phosphodiesterase and 5'-nucleotidase activities, moderate to strong phospholipase A and hyaluronidase activities, variable L-amino acid oxidase activity and were devoid of arginine ester hydrolase and thrombin-like activities. Some venom samples exhibited strong acetylcholinesterase activity. Venoms of M. c. dumerili and M. frontalis exhibited exceptionally high alkaline phosphomonoesterase activity while two of the M. f. fulvius venom samples tested exhibited strong hemorrhagic activity in mice. 2. The polyacrylamide gel electrophoretic patterns of the venoms indicate that most of the Micrurus venom proteins are basic proteins. All Micrurus venoms tested exhibited similar SDS-polyacrylamide gel electrophoretic patterns, with an intense low mol. wt protein band. 3. The Micrurus venoms appear to exhibit biological properties similar to other elapid venoms found in Asia and Africa. There are, however, no common characteristics in the biological properties of the venoms examined at the generic level.
...
PMID:The biological properties of venoms of some American coral snakes (Genus micrurus). 158 85

1. The hemorrhagic, procoagulant, anticoagulant, protease, arginine ester hydrolase, phosphodiesterase, alkaline phosphomonoesterase, 5'-nucleotidase, hyaluronidase, phospholipase A and L-amino acid oxidase activities of 50 venom samples from 20 taxa of rattlesnake (genera Crotalus and Sistrurus) were examined. 2. The results show that notwithstanding individual variations in the biological activities of Crotalus venoms and the wide ranges of certain biological activities observed, there are some common characteristics at the genus and species levels. 3. The differences in biological activities of the venoms compared can be used for differentiation of the species. Particularly useful for this purpose are the thrombin-like enzyme, protease, arginine ester hydrolase, hemorrhagic and phospholipase A activities and kaolin-cephalin clotting time measurements.
...
PMID:A comparative study of the biological activities of rattlesnake (genera Crotalus and Sistrurus) venoms. 167 59

1. The biological properties of twelve samples of venoms from all four species of Dendroaspis (mamba) were investigated. 2. Dendroaspis venoms generally exhibited very low levels of protease, phosphodiesterase and alkaline phosphomonoesterase; low to moderately low level of 5'-nucleotidase and very high hyaluronidase activities, but were devoid of L-amino acid oxidase, phospholipase A, acetylcholinesterase and arginine ester hydrolase activities. The unusual feature in venom enzyme content can be used to distinguish Dendroaspis venoms from other snake venoms. 3. All Dendroaspis venoms did not exhibit hemorrhagic or procoagulant activity. Some Dendroaspis venoms, however, exhibited strong anticoagulant activity. The intravenous median lethal dose of the venoms ranged from 0.5 microgram/g mouse to 4.2 micrograms/g mouse. 4. Venom biological activities are not very useful for the differentiation of the Dendroaspis species. The four Dendroaspis venoms, however, can be differentiated by their venom SDS-polyacrylamide gel electrophoretic patterns.
...
PMID:A comparative study of the biological properties of Dendroaspis (mamba) snake venoms. 168 21

1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase, hyaluronidase, alkaline phosphomonoesterase, 5'-nucleotidase, arginine ester hydrolase, phospholipase A, L-amino acid oxidase and protease activities of 30 samples of venoms from nine species (12 taxa) of the old world vipers (Subfamily Viperinae) including snakes from the genera Bitis, Causus, Cerastes, Echis, Eristicophis and Pseudocerastes, were determined and the Sephadex G-75 gel filtration patterns for some of the venoms were also examined. 2. Examination of the biological properties of the venoms of the Viperinae tested indicates the presence of common venom biological characteristics at the various phylogenic levels. 3. Venoms of most species of the Viperinae examined exhibited characteristic biological properties at the species level, and this allows the differentiation of the Viperinae species by differences in their biological properties. 4. Particularly useful for this purpose, are the effects of venom on kaolin-cephalin clotting time of platelet poor rabbit plasma and the Sephadex G-75 gel filtration pattern and arginine ester hydrolase activity of the venom.
...
PMID:A comparative study of the biological properties of venoms of some old world vipers (subfamily viperinae). 173 99

1. The protease, phosphodiesterase, alkaline phosphomonoesterase, L-amino acid oxidase, acetylcholinesterase, phospholipase A, 5'-nucleotidase, hyaluronidase, arginine ester hydrolase, procoagulant, anticoagulant and hemorrhagic activities of ten samples of venoms from seven taxa of sea snakes were examined. 2. The results show that venoms of sea snakes of both subfamilies of Hydrophiinae and Laticaudinae are characterized by a very low level of enzymatic activities, except phospholipase A activity and, for some species, hyaluronidase activity. 3. Because of the low levels of enzymatic activities and the total lack of procoagulant and hemorrhagic activities, venom biological properties are not useful for the differentiation of species of sea snakes. Nevertheless, the unusually low levels of enzymatic activities of sea snake venoms may be used to distinguish sea snake venoms from other elapid or viperid venoms.
...
PMID:A comparative study of the biological properties of some sea snake venoms. 176 14

1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase, alkaline phosphomonoesterase, 5'-nucleotidase, hyaluronidase, arginine ester hydrolase, phospholipase A, L-amino acid oxidase and protease activities of 26 samples of venoms from 13 species of Bothrops were determined, and the Sephadex G-75 gel filtration patterns for some of the venoms also examined. 2. The results show that while there are considerable individual variations in the biological activities of many of the Bothrops venoms tested, there are some common characteristics at the genus and species levels. 3. The differences in the biological properties of the Bothrops venoms tested can be used for the differentiation of most Bothrops species examined.
...
PMID:A comparative study of the biological properties of some venoms of snakes of the genus Bothrops (American lance-headed viper). 179 79


1 2 3 4 Next >>

---