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)

The release of plasma-membrane-bound enzymes by phosphatidylinositol-specific phospholipase C obtained from Bacillus thuringiensis was investigated. Among the ectoenzymes of plasma membrane tested, alkaline phosphodiesterase I was released markedly from rat kidney cortex slices, in addition to alkaline phosphatase and 5'-nucleotidase. Other membrane-bound enzymes; alanine aminopeptidase, leucine aminopeptidase, dipeptidyl peptidase, leucine aminopeptidase, dipeptidyl peptidase IV, esterase and gamma-glutamyl transpeptidase could not be liberated from the treated slices. Alkaline phosphodiesterase I was released linearly from rat kidney slices with the concentration of phosphatidylinositol-specific phospholipase C, but little enzyme was released from rat liver slices. Alkaline phosphodiesterase I separated from kidney tissue with n-butanol still retained phosphatidylinositol and was transformed into a lower molecular weight form by phosphatidylinositol-specific phospholipase C. This suggests an important function for phosphatidylinositol in the binding of alkaline phosphodiesterase I to the plasma membrane of rat kidney cells. The alkaline phosphodiesterase I released from rat kidney had a molecular weight of about 240,000 and an isoelectric point (pI) of 5.4. The enzyme hydrolyzed the phosphodiester linkage of p-nitrophenyl-thymidine 5'-monophosphate at pH 8.9 and had a Km value of 0.3 mM. The enzyme was activated by Mg2+ and Ca2+, but was inhibited by EDTA. Strong inhibition took place on the addition of adenosine 5'-phosphosulfate or the nucleotide pyrophosphates, i.e., UDP-galactose and alpha, beta-methylene ATP.
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PMID:Release of alkaline phosphodiesterase I from rat kidney plasma membrane produced by the phosphatidylinositol-specific phospholipase C of Bacillus thuringiensis. 609 28

The membrane-bound enzyme responsible for the breakdown of 3'-phosphoadenosine 5'-phosphosulfate (PAPS) has been purified 1,900-fold from detergent-solubilized human placenta, using chromatographies on Con A-Sepharose, Blue Sepharose, AMP-Agarose, and Sepharose CL-6B, and sucrose density gradient centrifugation. The enzyme required Mg2+ and showed the optimum activity at pH 9.4. The preparation was free of alkaline phosphatase [EC 3.1.3.1], phosphodiesterase [EC 3.1.4.1], and 5'-nucleotidase [EC 3.1.3.5] activities, which enabled investigation of the substrate specificity and kinetic properties of the enzyme without interference by secondary reactions due to the above activities. The enzyme cleaved the pyrophosphate linkages of NAD and various sugar nucleotides and the phosphodiester linkage of p-nitrophenyl-thymidine 5'-monophosphate (PNTP), as well as the phosphosulfate linkages of PAPS and its biosynthetic precursor, adenosine 5'-phosphosulfate (APS), with apparent Km values of 0.12-0.33 mM. Relative activities towards PNTP and PAPS did not change during the purification procedures starting from the homogenate. This, together with the data of kinetic studies using two substrates simultaneously, led us to conclude that the activities towards all the substrates tested were due to one and the same nucleotide pyrophosphatase.
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PMID:Substrate specificity of a nucleotide pyrophosphatase responsible for the breakdown of 3'-phosphoadenosine 5'-phosphosulfate (PAPS) from human placenta. 630 61