Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Horse liver alcohol dehydrogenase was reacted with glyoxal at different pH values ranging from 6.0 to 9.0. At pH 9.0 the enzyme undergoes a rapid activation over the first minutes of reaction, followed by a decline of activity, which reaches 10% of that of the native enzyme. Chemical analysis of the inactivated enzyme after sodium borohydride reduction shows that 11 argi-ine and 11 lysine residues per mole are modified. At pH 7.7 the enzyme activity increases during the first hour of the reaction with glyoxal and then decreases slowly. Chemical analysis shows that 4 arginine and 3 lysine residues per mole are modified in the enzyme at the maximum of activation. At pH 7.0 the enzyme undergoes a 4-fold activation. Chemical analysis shows that in this activated enzyme 3 lysine and no arginine residues per mole have been modified. Steady-state kinetic analysis suggests that the activated enzyme is not subjected to substrate inhibition and that its Michaelis constant for ethanol is three times larger than that of the native enzyme. The possible role of arginine and lysine residues in the catalytic function of liver alcohol dehydrogenase is discussed.
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PMID:The reaction of horse-liver alcohol dehydrogenase with glyoxal. 0 Dec 46

delta-Aminolaevulinic acid dehydratase catalyses the synthesis of porphobilinogen. The enzyme has a molecular mass of 285000 and is composed of eight similar subunits of molecular mass 35000. The N-terminal amino acid is acylated, and the number of peptides found on tryptic digestion equals the number of lysine and arginine residues per mass of 35000. The eight subunits are apparently arranged at the corners of a cube and therefore have dihedral (D4) symmetry. The bovine liver enzyme which has been cystallized contains 4--6 atoms of zinc per mole of enzyme. The apo-enzyme obtained on prolonged hydrolysis can be reactivated by the addition of zinc or cadmium ions. The dialysed enzyme must be first treated with dithiothreitol. There are two very active SH groups in a total of 6--7-SH groups per subunit. The substrate forms a Schiff base with the epsilon-amino group of a lysine residue. Reduction of the Schiff base with NaBH4 should reveal the number of active sites per mole of enzyme. It appears that only four of the eight subunits form a Schiff base with the substrate indicating that the enzyme exhibits the phenomenon of either half-site reactivity or negative cooperativity. The enzyme appears to have a strong subunit-subunit interaction for an immobilized preparation remained stable for at least a month. An immobilized enzyme preparation was treated in a manner so that it dissociated into tetramers. Both the eluate and protein still attached to the Sepharose on a column were enzymically active. The bound enzyme could not reassociate under assay conditions but still contained about 50% of the original enzyme activity. It would seem that the enzyme is active when composed with less than eight subunits.
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PMID:5-Aminolaevulinic acid dehydratase: structure, function, and mechanism. 0 32

The membrane penicillinase of Bacillus licheniformis 749/C has been demonstrated to be a phospholipoprotein. The homogeneous enzyme gives a positive reaction for phosphorous and for unsaturated fatty acids, has a molecular weight of 33,000 in contrast to 29,000 for the exoenzyme, and contains 8 to 9 additional residues of aspartate or asparagine, 4 to 5 of serine, 7 of glutamate or glutamine, and 4 to 5 of glycine per mole. The COOH-terminal sequence of both membrane and exoenzymes is -Met-Asn-Gln-Lys-COOH; hence the extra peptide portion present in the membrane enzyme is not attached to the COOH-terminus of the exoenzyme. Procedures which readily detected the lysine residue at the NH2 terminus of the exoenzyme did not yield a positive test with the membrane form. The NH2 terminus of the membrane enzyme may be blocked by or linked to the phospholipid. A procedure for the preparation of membrane penicillinase on a large scale and an improved method for purification of the exoenzyme have been developed.
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PMID:Purification of plasma membrane penicillinase from Bacillus licheniformis 749/C and comparison with exoenzyme. 0 71

Interactions between tranexamic acid and protein were studied in respect of the antifibrinolytic actions of tranexamic acid. Tranexamic acid did neither show any interaction with fibrinogen or fibrin, nor was incorporated into cross-linked fibrin structure by the action of factor XIII. On the other hand, tranexamic acid bound to human plasmin with a dissociation constant of 3.5 X 10-5 M, which was very close to the inhibition constatn (3.6 X 10-5 M1 for this compound in inhibiting plasmin-induced fibrinolysis. The binding site of tranexamic acid on plasmin was not the catalytic site of plasmin, because TLCK-blocked plasmin also showed a similar affinity to tranexamic acid (the dissociation constant, 2.9-4.8 x 10-5m). in the binding studies with the highly purified plasminogen and TLCK-plasmin preparations which were obtained by affinity chromatography on lysine-substituted Sepharose, the molar binding ratio was shown to be 1.5-1.6 moles tranexamic acid per one mole protein. On the basis of these and other findings, a model for the inhibitory mechanism of tranexamic acid is presented.
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PMID:Plasminogen-plasmin system IX. Specific binding of tranexamic acid to plasmin. 12 63

A polypeptide with a molecular weight of 8 500 (HP 8 500) was isolated from the mitochondrial membrane of the nuclear mutant cni-1 of Neurospora crassa. This mutant is characterized by a cyanide-insensitive respiration and by a deficiency in the cytochromes aa3 and b. The polypeptide is synthesized on mitochondrial ribosomes. It has an extremely hydrophobic character; it is insoluble in aqueous media in the absence of sodium dodecylsulfate and is soluble in acid chloroform/methanol. It lacks histidine. The polar amino acids lysine, arginine, aspartic acid, glutamic acid, serine and threonine make up only 25% of the total amino acids on a mole-percent basis. The N-terminal amino acid is tyrosine. The possible function of this polypeptide in the mitochondrial membrane is discussed.
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PMID:Isolation and characterization of a mitochondrially synthesized polypeptide from Neurospora crassa cni-1 mutant. 12 27

During the inactivation of the nucleotide-free F1-ATPase at pH 7.0, by p-fluorosulfonyl[14C]benzoyl-5'-adenosine ([14C]FSBA) in the presence of 20% glycerol, about 4.5 g atoms of 14C are incorporated/350,000 g of enzyme. Isolation of the subunits has shown: (a) over 90% of the incorporated label is associated with the alpha and beta subunits; (b) the amount of label incorporated into the alpha subunit is about 0.5 g atoms/mol which is nonspecifically associated with a number of tyrosine and lysine residues; (c) the amount of radioactivity incorporated into the beta subunit is about 0.9 g atoms/mol which correlates with the degree of inactivation of the enzyme and resides on a single tyrosine residue; (d) up to 2.2 mol of alpha subunit have been isolated from each mole of inactivated enzyme; and (e) about 2 mol of beta subunit have been isolated from each mole of inactivated enzyme. These results account for the incorporation of 4.5 g atoms of 14C which are incorporated/mol of ATPase during inactivation if there are three copies each of the alpha and beta subunit present in the enzyme. It has also been shown that 4-chloro-7-nitrobenzofurazan (NBD-Cl) and FSBA react with different tyrosine residues when they inactivate the ATPase. In addition, it has been shown that the ATPase inactivated with FSBA retains the capacity to bind up to 2.2 mol of [14C]ADP/350,000 g of enzyme.
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PMID:On the subunit stoichiometry of the F1-ATPase and the sites in it that react specifically with p-fluorosulfonylbenzoyl-5'-adenosine. 15 96

Antibodies to chromatin proteins of Novikoff hepatoma cells formed precipitin bands in the double-diffusion immunoprecipitation assay with chromatin proteins of Novikoff hepatoma, Walker 256 carcinosarcoma, and 18-day fetal rat liver. The antigen used for preparation of antiserum was the chromatin proteins initially extracted with 3 M NaCl-7 M urea and soluble after dialysis to 0.14 M NaCl-0.35 M urea. The chromatin proteins used for analytical studies were extracted with 0.6 M NaCl containing 0.01 M Tris-HCl (pH 8) and 100 muM phenylmethylsulfonyl fluoride. Corresponding chromatin proteins of normal and 18-hr regenerating rat liver, heart, and kidney did not form precipitin bands. The antigen was purified from the chrmatin of Novikoff hepatoma cells by exclusion chromatography on Sephadex G-150 and preparative nondenaturing polyacrylamide gel electrophoresis. Its migration on denaturing sodium dodecyl sulfate-polyacrylamide gels corresponded to a molecular weight of 26,000. Amino acid analysis showed that the ratio of acidic to basic amino acids was 1.4 to 1.0. Evidence for its homogeneity included its migration as a single protein spot on two-dimensional polyacrylamide gel electrophoresis and its single lysine amino-terminal amino acid. This protein is a glycoprotein, as shown by the presence of 15 moles of galactosamine per mole of antigen. These studies demonstrate the presence of a fetal glycoprotein in the chromatin of two tumors that may have an important role in determining their gene products.
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PMID:A fetal protein in chromatin of Novikoff hepatoma and Walker 256 carcinosarcoma tumors that is absent from normal and regenerating rat liver. 18 70

The UDP-apiose/UDP-xylose synthase from cell suspension cultures of parsley has been purified 1400-fold by an improved method. The ratio of apiose to xylose formed from UDP-D-glucuronic acid (UDP-GlcUA) remained constant throughout the purification procedure. Dodecylsulfate-gel electrophoresis and sedimentation equilibrium measurements showed that this enzyme preparation is composed of two proteins with molecular weights of 65000 and 86000. The two proteins which are present in a molar ratio of about 1:0.7 to 1:0.9 could not be separated by ammonium sulfate fractionation, chromatography on DEAE-cellulose at different pH-values, and on omega-aminoalkyl-Sepharose, and by gel filtration on Acrylex P-100. Each protein is composed of two apparently identical subunits. The presence of only two different subunits was confirmed by end group analysis in which glycine was found as N-terminal amino acid for the larger and lysine for the smaller protein. Crosslinking with dimethylsuberimidate gave dimers of the identical subunits but no hybrids. Separation of the two proteins was achieved on DEAE-cellulose in the presence of urea. After dialysis only the 86000-Mr protein showed enzyme activity with no significant change in the apiose/xylose ratio. However, in the absence of the 65000-Mr protein enzyme stability was decreased drastically. By equilibrium dialysis it was found that 0.5 mol UDP-GlcUA are bound per mole of 86000-Mr protein. NAD+ alone was not bound, but in the presence of UDP it was also bound in a ratio of 0.5 mol/mol catalytic protein. Experiments in which sodium borohydride was added to the enzyme incubation gave no indication that the 4-keto intermediate is bound as a Schiff base to the enzyme. Also no evidence for epimerization at C-3 of the 4-ulose intermediate prior to ring contraction to apiose was found.
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PMID:UDP-apiose/UDP-xylose synthase. Subunit composition and binding studies. 19 51

To examine the role of lysyl residues in the activity of the enzyme, phosphoglyceromutase (PGM) from chicken breast muscle was chemically modified with trinitrobenzenesulfonate (TNBS) and pyridoxal 5'-phosphate. Trinitrophenylation resulted in modification of about nine lysines per mole of PGM with almost complete activity loss. Substrate (3-PGA) offered some protection to TNBS inactivation but cofactor (2,3-DPGA) did not. Reduction of the Schiff's base complex between pyridoxal 5'-phosphate and PGM gave irreversible inactivation of the enzyme. Inactivation was due to incorporation of 1 mol of pyridoxal 5'-phosphate per mole of PGM dimer through the epsilon-amino group of a lysyl residue. The effect of pyridoxal 5'-phosphate was specific for intact native enzyme and reaction with only one lysine per dimer was not due to induced conformational changes nor to dissociation of the reacted enzyme. 3-PGA prevented much of the reaction with pyridoxal 5'-phosphate with preservation of 70% of the activity and was a competitive inhibitor of the active site directed reagent. Cofactor (2,3-DPGA) acting noncompetitively, reduced the rate at which inactivation occurred with pyridoxal 5'-phosphate. Incorporation of 2,3-[32P]DPGA into PGM irreversibly inactivated with pyridoxal 5'-phosphate and NaBH4 was incomplete indicating hindrance to phosphorylation in the modified enzyme. The results indicate that a lysyl residue is located at or near the active site of PGM and that it is probably involved in the binding of 3-PGA.
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PMID:Studies on phosphoglyceromutase from chicken breast muscle: chemical modification of lysyl residues. 19 26

The reaction of the phosphate residue transfer catalysed by histone kinase dependent on adenosine 3':5'-monophosphate (cyclic AMP) was studied. The phosphotransferase reaction was shown to obey the mechanism of ping-pong bi-bi type. After incubation of the catalytic subunit of histone kinase with [gamma-32P]ATP the incorporation of one mole of [32P]phosphage per mole of protein was observed. The tryptic [32P]phosphohistidine-containing peptide was isolated and its N-terminus and amino acid composition were determined. The 2',3'-dialdehyde derivative of ATP (oATP) was used as the affinity label for the catalytic subunit of cyclic-AMP-dependent histone kinase. The inhibitor formed an alidmine bond with epsilon-amino group of the lysine residue of the active site and was irreversibly bound to the enzyme after reduction by sodium borohydride with concurrent irreversible inactivation of the enzyme. After inactivation, about one mole of 14C-labelled inhibitor was incorporated per mole of the enzyme. ATP effectively protected the catalytic subunit of histone kinase against inactivation by oATP. Tryptic digestion of the enzyme-inhibitor complex led to the isolation of the 14C-labelled peptide of the active site of histone kinase. Basing on these results, the role of histidine and lysine residues in the active site of the catalytic subunit of histone kinase was suggested.
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PMID:Studies on the mechanism of action of histone kinase dependent on adenosine 3':5'-monophosphate. Evidence for involvement of histidine and lysine residues in the phosphotransferase reaction. 20 63


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