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

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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)

A lipolytic zinc-copper protein has been isolated from the cytosol of chick liver. This material had a molecular weight of 6000 daltons, contained four atoms of zinc and one atom of copper per molecule. The 6000 dalton fraction aggregated at high ionic strength or in the presence of sodium dodecyl sulphate. Lipolytic activity was observed towards triolein, tripalmitin , phosphatidyl choline and retinyl palmitate, and was stimulated by cholate, Ca and high NaCl concentrations, and was inhibited by sulphydryl reagents, inhibitors of serine esterases, alkaline phosphatase and chelating agents. It appears that this copper-zinc protein is distinct from metallothionein which has no lipolytic activity.
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PMID:A low molecular weight zinc-copper lipolytic protein from chick liver. 672 48

To investigate the role of protein p3 in bacteriophage phi 29 initiation of replication, we have studied the nature of the covalent linkage between protein p3 and phi 29 DNA. The protein-DNA compound was digested with micrococcal nuclease and pronase resulting in a nucleotidyl-peptide that was further digested by alkaline phosphatase and snake venom phosphodiesterase yielding 5'-dAMP. The DNA-protein linkage is sensitive to alkali. Treatment of the nucleotidyl-peptide with 0.1 M NaOH at 37 degrees C for 3 hr after phosphatase digestion released 5'-dAMP. Hydrolysis of the nucleotidyl-peptide with 5.8 M HCl at 110 degrees C for 90 min yielded O-phosphoserine. These results, together with the sensitivity of the DNA-protein linkage to snake venom phosphodiesterase and its resistance to hydroxylamine, indicate that protein p3 is covalently linked to phi 29 DNA through a phosphoester bond between L-serine and 5'-dAMP, namely a O,5'-deoxyadenylyl-L-serine bond.
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PMID:Protein p3 is linked to the DNA of phage phi 29 through a phosphoester bond between serine and 5'-dAMP. 677 79

The nature of the protein kinase (PK) which phosphorylates the core protein of hepatitis B virus in vitro was studied. The PK copurified with the core particles during rate zonal centrifugation and gel chromatography. It showed the same size heterogeneity as the core particles, which consisted of a main fraction of 28-nm particles and a subfraction of 22- to 26-nm particles. DNA-containing heavy core particles with a density of 1.33 to 1.35 g/ml and less endogenous PK than did the light cores. The phosphorylation reaction had a rapid initial phase (several minutes) and a slow but long-lasting second phase (many hours). The PK had a high affinity for ATP (KM = 0.5 mumol/liter). Only few of the several hundred P21.9 subunits in one core particle were phosphorylated in vitro. The only amino acid which was phosphorylated in vitro was serine. The resistance of the introduced phospho group against alkaline phosphatase showed that the PK acceptor, and probably the enzyme itself, was located inside the core particle.
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PMID:Specificity and localization of the hepatitis B virus-associated protein kinase. 680 56

Cadmium-113 nuclear magnetic resonance (113Cd NMR) has been used to probe the binding characteristics of 113Cd2+ to the three classes of metal binding sites in Escherichia coli alkaline phosphatase to help elucidate the molecular origin of the metal ion dependent "half-sites" reactivity exhibited by this dimeric Zn2+ metalloenzyme [Otvos, J.D., Armitage, I.M., Chlebowski, J.F., & Coleman, J.E. (1979) J. Biol. Chem. 254, 4707-4713]. In the absence of phosphate, the first two 113Cd2+ ions added to the apodimer give rise to a single 113Cd resonance (169 ppm), indicating selective binding to the pair of symmetrically disposed A sites. Resonances arising from additional 113Cd2+ bound to the B and C sites cannot be observed; B- and/or C-site occupation also renders the A-site 113Cd resonance undetectable. Both these observations have been attributed to severe chemical exchange broadening in the A-, B-, and C-site 113Cd signals induced by an unknown modulation process(es). Interestingly, covalent phosphorylation of the active-site serine residues abolishes this exchange modulation, allowing three separate resonances to be detected and assigned to 113Cd2+ located at each of the three classes of metal binding sites in the enzyme. By varying the metal composition of the phosphorylated enzyme, we have characterized the correlations that exist between the chemical shifts ana intensities of these 113Cd resonances and the metal occupancies of the A, B, and C sites in the individual subunits. This information has allowed us to conclude that the half-sites phosphorylation of the Cd2 2+ enzyme is accompanied by a slow migration of half the Cd2+ originally located at the A sites to the B sites on the phosphorylated subunits. The driving force for this metal redistribution, which at equilibrium leaves half the subnits devoid of metal ion and thereby incapable of binding phosphate, is apparently the dramatic stabilization of the complex of Cd2+ with the B sites, which was demonstrated to occur in those subunits that become phosphorylated. From the kinetics of both phosphorylation and metal redistribution in Cd2 2+ enzyme, we suggest that population of the A and B sites in a subunit, rather than the A site alone, constitutes the minimum requirement for induction of catalytic function in alkaline phosphatase. The spin relaxation properties of the enzyme-bound 113Cd2+ ions are also briefly discussed.
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PMID:Determination by cadmium-113 nuclear magnetic resonance of the structural basis for metal ion dependent anticooperativity in alkaline phosphatase. 699 15

The complete amino acid sequence of the Escherichia coli alkaline phosphatase subunit [orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1, isozyme 3] has been determined. The monomer contains 449 amino acid residues in a single unglycosylated polypeptide chain having a calculated Mr of 47,029. Isozyme 1 has an additional arginine residue at the NH2 terminus that presumably results from variability in processing of precursor molecules. Sequence data were obtained from both manual and automatic Edman degradation of the tryptic and cyanogen bromide peptides, as well as other peptides derived therefrom. The two disulfide bonds were determined from analyses of the appropriate peptic peptides. This structure confirms earlier reports of the sequence surrounding the active-site serine and both the NH2- and COOH-terminal cyanogen bromide fragments. A secondary structure prediction places nearly half the residues in alpha-helical segments that have 13% and 16%, respectively, in beta-strand and beta-turn orientations.
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PMID:Amino acid sequence of Escherichia coli alkaline phosphatase. 702 51

Cadmium can replace zinc and magnesium in alkaline phosphatase from Escherichia coli, which permits the characterization of the catalytically important metal-binding sites by 113Cd NMR. At pH 6.5, in the absence of phosphate, two equivalents of cadmium are bound in identical sites (A), one in each monomer. Either raising the pH or phosphorylation of Cd2AP (AP is apoalkaline phosphatase) results in migration of Cd(II) from the site A in one monomer to the opposite monomer to occupy a second site (B) adjacent to the A site in the first monomer, a site stabilized by phosphorylation or high pH. At pH 6.5 in the presence of phosphate, the 113Cd NMR spectrum of Cd6AP consists of three narrow resonances from three pairs of fully occupied sites, A, B, and C. The resonances at 153 and 70 ppm represent two metal sites (A and B) 3.9 A apart at each active center and adjacent to the serine phosphorylated during turnover. At this pH the enzyme exists almost exclusively as the covalent phosphoseryl form E-P with a 31P resonance at approximately 9 ppm. As the pH is raised a 31P signal from the noncovalent E.P complex appears at approximately 13 ppm. This is reflected in the 113Cd spectrum by a split of both the A- and B-site resonances into pairs, a set at 137 and 65 ppm for E.P, and 153 and 70 ppm for the E-P species. 113Cd-O-31P coupling of 30 Hz on the 31P resonance of E.P shows the noncovalently bound phosphate to be coordinated to one but not both metal ions at each active site. The resonance of E-P is not coupled and thus the phosphoseryl residue appears to shift out of the coordination sphere of the active site metal ion.
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PMID:113Cd NMR of Cd(II)-substituted Zn(II) metalloenzymes. 714 Sep 97

1. Acid phosphatase (AcPase) from potato tubers was purified by tannic acid fractionation, DEAE-cellulose chromatography, filtration on Bio-Gel P-150 and affinity chromatography on Con A-Sepharose. The enzyme was purified 260-fold and was electrophoretically homogeneous; its mol. mass is about 69 000. 2. The carbohydrate component accounts for 16.6% of the total enzyme weight and includes mannose (5.6%), rhamnose (3.4%), glucose (2.5%), galactose (1.5%) and glucosamine (3.6%). In the amino acid composition aspartic acid, glutamic acid, serine and glycine account for 37.7% of total amino acid residues. 3. Optimum pH is at 5.0-5.3. The enzyme activity was reduced by half after 30 min incubation at 60 degrees C, and was fully abolished after 2 h incubation at 70 degrees C. The enzyme is a nonspecific phosphomonoesterase; aromatic phosphomonoesters and inorganic pyrophosphate can serve as substrates. Apparent Km values were 1.25 mM and 40 mM for p-nitrophenylphosphate and inorganic pyrophosphate, respectively. The enzyme is inhibited by MoO42-, Zn2+, Hg2+ and urea. Inhibition caused by urea was reversible at urea concentration below 9 M.
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PMID:Acid phosphatase of potato tubers (Solanum tuberosum L). Purification, properties, sugar and amino acid composition. 715 77

The synthesis and phosphorylation of influenza virus nucleoprotein and nonstructural protein were analyzed. The nucleoprotein (NP) was found to be phosphorylated in both infected cells and in isolated virions. The phosphate is in a monoester linkage to a serine residue. Two-dimensional tryptic peptide maps of the 32P-labeled protein, as well as measurements of specific activity, suggests that NP is phosphorylated at one site per molecule. The viral nonstructural (NS 1) protein is also phosphorylated, but on threonine residues. Up to a maximum of two sites per NS 1 molecule could be so modified in infected cells, as demonstrated by two different methods of tryptic peptide analysis and by measurements of the ratio of 32P to 3H-amino-acids incorporated into NS 1 protein species. The NS 1 protein is resolved into four major species of differing isoelectric point in a two-dimensional electrophoretogram. The most acidic species was found to have two phosphorylated sites per molecule, and the next most acidic species contained on the average one phosphate per molecule. Treatment of the phosphorylated species with bacterial alkaline phosphatase demonstrated that the level of phosphorylation is the only identifiable difference between the phosphorylated and unphosphorylated NS 1 species. The distinction between the two unphosphorylated species could not be determined. The distribution of the un-, mono-, and diphosphorylated NS 1 species was characterized at different times after synthesis. These modifications were found to occur very rapidly after translation (30 to 60 s), after transport of the unmodified species from cytoplasm to nucleus of the infected cell. The phosphorylation of NP also takes place rapidly after its synthesis; the site within the cell of the NP phosphorylation has not been unambiguously determined.
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PMID:The structure and synthesis of influenza virus phosphoproteins. 724 Jan 43

The site-specific phosphorylation of initiation factor 2 (eIF-2) by three different cyclic nucleotide-independent protein kinases from rabbit reticulocytes was examined. The hemin-controlled repressor modified serine in the alpha subunit (Mr = 38,000), while casein kinase II and protease-activated kinase II phosphorylated serine residues of the beta subunit (Mr = 53,000). Under conditions of maximal phosphorylation, 1 mol of phosphate was incorporated into eIF-2 by each of the protein kinases. However, following treatment of eIF-2 with alkaline phosphatase, 2 mol of phosphate were added by casein kinase II, indicating residual phosphate was present on the beta subunit of purified eIF-2. The tryptic and chymotryptic peptides of the phosphorylated subunits were analyzed by two-dimensional peptide mapping involving thin layer electrophoresis followed by ascending chromatography. When eIF-2 was phosphorylated by the hemin-controlled repressor, three major chymotryptic and four tryptic phosphopeptides with molecular weights ranging from approximately 600 to 3000 were identified. When phosphorylation of eIF-2 beta was examined, two tryptic and two chymotryptic phosphopeptides were obtained after phosphorylation with casein kinase II and were different from the phosphopeptides observed following phosphorylation with protease-activated kinase II. This indicates that three distinct sites in the beta subunit were phosphorylated, two by casein kinase II and one by protease-activated kinase II.
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PMID:Site-specific phosphorylation if initiation factor 2 by three cyclic nucleotide-independent protein kinases. 743 Jan 64

In wild-type strains of Escherichia coli, alkaline phosphatase (AP), either when present as a soluble protein or when fused to a membrane protein, is only active after translocation to the periplasm. In thioredoxin reductase (trxB) mutants, however, cytoplasmically localized AP can form disulphide bonds and can reach an active conformation. Once it has folded in the cytoplasm, it can no longer be translocated. On the other hand, when AP is fused to periplasmic domains of a membrane protein, translocation can be more rapid than folding. Thus, expressing hybrids of AP and integral membrane proteins in a trxB mutant generates competition between folding of AP in the cytoplasm and its translocation to the periplasm. The cellular localization of AP can be monitored in phosphoserine phosphatase (serB) mutants causing auxotrophy for L-serine. Cytoplasmically but not periplasmically localized AP can compensate for the lack of SerB, leading to growth on indicator plates. As expected, when AP was fused to cytoplasmic domains of membrane proteins, serB-mediated auxotrophy was abolished. Surprisingly, AP fusions to periplasmic domains exhibited a non-uniform response pattern. Fusions that translocate AP rapidly did not complement the SerB defect, while those that export AP only slowly could do so. The usefulness of these strains for studying a variety of aspects related to membrane protein biogenesis is discussed.
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PMID:Synthetic competition between cytoplasmic folding and translocation of a soluble membrane protein domain. 765 6


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