Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

4-Nitrophenyl and 2-napthyl monoesters of phenylphosphonic acid have been synthesized, and an enzyme catalyzing their hydrolysis was resolved from alkaline phosphatase of a commerical calf intestinal alkaline phosphatase preparation by extensive ion-exchange chromatography, chromatography on L-phenylalanyl-Sepharose with a decreasing gradient of (NH4) 2SO4, and gel filtration. Detergent-solubilized enzyme from fresh bovine intestine was purified after (NH4)2SO4 fractionation by the same technique. The purified enzyme is homogeneous by polyacrylamide gel electrophoresis and sedimentation equilibrium centrifugation. It has a molecular weight of 108,000, contains approximately 21% carbohydrate, and has an amino acid composition considerably different from that reported from alkaline phosphatase from the same tissue. The homogeneous intestinal enzyme, an efficient catalyst of phosphonate ester hydoolysis but not of phosphate monoester hydrolysis, was identified as a 5'-nucleotide phosphodiesterase by its ability to hydrolyze 4-nitrophenyl esters of 5'-TMP but not of 3'-TMP. Also consistent with this identification was the ability of the enzyme to hydrolyze 5'-ATP to 5'-AMP and PPi, NAD+ to 5'-AMP and NMN, TpT to 5'-TMP and thymidine, pApApApA to 5'-AMP, and only the single-stranded portion of tRNA from the 3'-OH end. Snake venom 5'-nucleotide phosphodiesterase also hydrolyzes phosphonate esters, but 3'-nucleotide phosphodiesterase of spleen and cyclic 3',5'-AMP phosphodiesterase do not. Thus, types of phosphodiesterases can be conveniently distinguished by their ability to hydrolyze phosphonate esters. As substrates for 5'-nucleotide phosphodiesterases, phosphonate esters are preferable to the more conventional esters of nucleotides and bis(4-nitrophenyl) phosphate because of their superior stability and ease of synthesis. Furthermore, the rate of hydrolysis of phosphonate esters under saturating conditions is greater than that of the conventional substrates. At substrate concentrations of 1 mM the rates of hydrolysis of phosphonate esters and of nucleotide esters are comparable and both superior to that of bis(4-nitrophenyl) phosphate.
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PMID:Hydrolysis of phosphonate esters catalyzed by 5'-nucleotide phosphodiesterase. 17 Sep 64

An enzyme capable of hydrolyzing 4-methylumbelliferyl phenylphosphonate to 4-methylumbelliferone and phenylphosphonic acid has been detected in human serum. It has a Km value of 1.72 x 10(-4) mol/L, has an optimum pH of 8.8-9.1 in Tris buffer, and shows maximum activity at 60 degrees C (30 min). The enzymic activity can be inhibited by Na3PO4, EDTA, and cysteine. We saw no effect of CuSO4, adenosine, thymidine, NaN3, diethyl p-nitrophenyl phosphate, p-chloromercuribenzoate, isopropyl fluorophosphate, or eserine on the enzymic activity. The enzyme cannot hydrolyze substrates of phosphodiesterase I or alkaline phosphatase. The enzyme is considered a phosphonate esterase.
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PMID:Specific detection and properties of enzyme hydrolyzing phosphonate ester in serum. 154 54

We examined the effect of phosphonoformic acid (PFA) and phosphonoacetic acid (PAA) upon Na+-Pi cotransport in brush-border membrane (BBM) from small gut of rat. Both PFA and PAA inhibited the Na+ gradient-dependent uptake of 32Pi by BBM vesicles (BBMV) prepared from intestinal mucosa but had no effect on Na+-dependent uptakes of D-[3H]glucose, L-[3H]proline, or [14C]succinate. The uptake in the absence of Na+ gradient, or uptake at equilibrium period (180 min), was not affected by PFA or by PAA. A chemical analogue of PFA and PAA, phosphonopropionic acid, had only a minor inhibitory effect and phenylphosphonic acid was inactive. Neither PFA nor PAA influenced the activity of rat intestinal BBM alkaline phosphatase. The BBMV from rat jejunum had a much higher capacity for Na+ gradient-dependent uptake of 32Pi than BBMV from duodenum or ileum. The inhibition of BBMV 32Pi transport across rat jejunum by PFA is competitive. We suggest that PFA and PAA are specific inhibitors of Na+ gradient-dependent uptake of Pi by BBMV from small intestinal mucosa and that they could serve as useful experimental tools for the studies of intestinal Na+-Pi cotransport.
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PMID:Inhibition of Na+-Pi cotransporter in small gut brush border by phosphonocarboxylic acids. 295 Jul 71

We investigated interactions of phosphonoformic acid (PFA), phosphonoacetic acid (PAA), and other phosphonyl derivatives with the Na+ gradient [Na+ extravesicular greater than Na+ intravesicular; Nao+ greater than Na+i]-dependent transport system for phosphate (Pi) in renal cortical brush border membrane vesicles (BBMV). PFA and PAA inhibited in a dose-dependent manner the Na+ gradient [Na+o greater than Na+i]-dependent uptake of Pi by rat kidney BBMV. PFA was a more potent inhibitor than PAA while phosphonopropionic acid, hydroxymethylphosphonic acid, and phenylphosphonic acid had no effect on Pi transport. The inhibitory effect of PFA was competitive (Ki approximately equal to 4.6 X 10(-4) M) and reversible upon dilution. The uptake of Pi by BBMV in the absence of Na+ gradient [Nao+ = Na+i] was also inhibited by PFA. The PFA had no effect on uptake of L-[3H]proline, D-[3H]glucose, or 22Na+ by BBMV nor did it alter intravesicular volume of BBMV. The relative (%) extent of inhibition by PFA was not altered by changes in the extravesicular pH or changes in the steepness of the Na+ gradient [Nao+ greater than Na+i]. The inhibition of PFA was analogous in renal BBMV from rats, mice, rabbits, or dogs. Unlike other known inhibitors of brush border membrane (BBM) transport of Pi, e.g. arsenate, NAD, and ethane-1-hydroxy-1,1-diphosphonate, PFA and PAA had no inhibitory effect on BBM-bound or solubilized alkaline phosphatase. Also, PFA did not interfere with the activity of renal cortical (Na-K)ATPase. Administration of PFA (0.5 g/kg/day, intraperitoneally) to thyroparathyroidectomized rats fed a low Pi diet elicited an increase in urinary excretion of Pi, but did not change the excretion of Na+, K, and Ca2+. The results show that the PFA, and to a lesser degree PAA, are specific competitive inhibitors of the Na+-Pi cotransport in renal cortical BBM and are suitable probes for studies of this transport system.
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PMID:Phosphonocarboxylic acids as specific inhibitors of Na+-dependent transport of phosphate across renal brush border membrane. 300 55