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

An acid protease produced by the thermophilic fungus Penicillium duponti K 1014 has been purified by consecutive ion-exchange and gel permeation chromatography, and crystallized from aqueous acetone solution. The purified endopeptidase gave a symmetrical schlieren peak by sedimentation velocity, and was found to be homogeneous upon disc gel electrophoresis at pH 9.5. The enzyme was most active at pH 2.5 against milk casein and showed high thermostability. An isoelectric point of 3.81 was found by isoelectric focusing. A minimum molecular weight of 41 590 was calculated from the amino acid composition, adopting an arginine content of one residue per mole of enzyme. This minimum molecular weight is in good agreement with the value of 41 000 previously found by gel permeation (Hashimoto, H., Iwaasa, T., and Yokotsuka, T. (1973), Appl. Microbiol. 25, 578). Besides the thermostability, the purified P. duponti protease differs from other well-characterized acid proteases in that it contains carbohydrate, 4.33% expressed as glucose. The enzyme was not affected by p-bromophenacyl bromide, but was completely inactivated by alpha-diazo-p-bromoacetophenone, diazoacetyl-DL-norleucine methyl ester, and diazoacetylglycine ethyl ester, in the presence of Cu2+. The complete inactivation of the protease by diazoacetyl-DL-norleucine methyl ester resulted in the specific incorporation of 1 mol of norleucine/mol of enzyme. On the basis of similar behavior of other acid proteases toward this inactivator, the results suggest the presence at the active site of an unusually reactive carboxyl group, involved in the catalytic function. The naturally occurring pepsin inhibitor of Streptomyces naniwaensis [Murao, S., and Satoi, S. (1970), Agric. Biol. Chem. 34, 1265] inhibited also the protease, at a threefold molar excess with respect to the enzyme.
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PMID:Purification and properties of the thermostable acid protease of Penicillium duponti. 0 87

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 alkaline phosphatase (orthophosphoric monoester phosphydrolase, EC 3.1.3.1) of Bacillus licheniformis MC14 was studied in an attempt to determine the number of subunits contained in the 120,000-molecular-weight native enzyme. Two moles of arginine was liberated per mole of native enzyme by carboxypeptidases A and B in the presence of sodium dodecyl sulfate. The effect on the native enzyme of progressively lowering the solvent buffer pH was monitored by determining the molecular weight by sedimentation equilibrium analysis, the sedimentation coefficient, the frictional coefficient, and the percent alpha-helix content of the enzyme. The alkaline phosphatase dissociates into two subunits around pH 4. At pH 2.8 a further decrease in S value, but no change in molecular weight, is observed, indicating a change in conformation. The frictional coefficients and percent alpha-helix content agree with this interpretation. A subunit molecular weight of 59,000 was calculated from sodium dodecyl sulfate gels.
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PMID:Subunits of the alkaline phosphatase of Bacillus licheniformis: chemical, physicochemical, and dissociation studies. 1 Feb 80

1. The total Mg in isolated fibres of Balanus aquila was 10-5 m-mole/kg wet wt. 2. The intracellular free Mg was measured by a null point method using Eriochrome Blue as an indicator of free Mg, and internal dialysis with solutions of varying ionized Mg concentrations. The results indicated a free Mg of 6 mM or 4-2 m-mole/kg wet wt. in the intracellular water immediately surrounding the dialysis capillary. 3. The ATP concentration was estimated to be 4-9 m-mole/kg wet wt. 4. A tentative partitioning of Mg among various intracellular constitutents based on present data combined with published work by others is (m-mole/kg wet wt): free, 4-2; MgATP, 4-2; myofibrillar bound, 1; residual (presumably bound to arginine phosphate and phosphate) ca. 1.
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PMID:The concentration of ionized magnesium in barnacle muscle fibres. 1 2

Arginyl-tRNA synthetase from Escherichia coli K12 has been purified more than 1000-fold with a recovery of 17%. The enzyme consists of a single polypeptide chain of about 60 000 molecular weight and has only one cysteine residue which is essential for enzymatic activity. Transfer ribonucleic acid completely protects the enzyme against inactivation by p-hydroxymercuriben zoate. The enzyme catalyzes the esterification of 5000 nmol of arginine to transfer ribonucleic acid in 1 min/mg of protein at 37 degrees C and pH 7.4. One mole of ATP is consumed for each mole of arginyl-tRNA formed. The sequence of substrate binding has been investigated by using initial velocity experiments and dead-end and product inhibition studies. The kinetic patterns are consistent with a random addition of substrates with all steps in rapid equilibrium except for the interconversion of the cental quaternary complexes. The dissociation constants of the different enzyme-substrate complexes and of the complexes with the dead-end inhibitors homoarginine and 8-azido-ATP have been calculated on this basis. Binding of ATP to the enzyme is influenced by tRNA and vice versa.
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PMID:Arginyl-tRNA synthetase from Escherichia coli K12. Purification, properties, and sequence of substrate addition. 3 99

Proteolytic activities were measured in extracts of human skin melanoma, lymphatic metastasis and in nonmalignant naevi by using various proteinase substrates as well as plasminogen activator assay. pH-optima for hydrolysis of various proteinase substrates by these tumors were found to be essentially the same as in healthy human skin. Melanoma extracts were found to especially readily hydrolyze N-alpha-benzoyl-DL-arginine beta-naphthylamine (BANA) at pH 5.8 in the presence of 1 mmol/l dithiothreitol and EDTA (cathepsin B1-like enzyme) as well as histones and p-tosyl-L-arginine methyl ester (TAME) at pH 7.5, and showed increased capacity to activate plasminogen when compared to nonmalignant naevus. The possible role of proteinases in malignant melanoma is discussed.
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PMID:Proteolytic enzymes and plasminogen activator in melanoma. 3 88

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

Angiotensin-converting enzyme has been solubilized from a particulate fraction of rabbit lung and purified to apparent homogeneity in 11% yield by a procedure including fractionation with DEAE-cellulose and calcium phosphate gel, elution from Sephadex G-200, and lectin affinity chromatography. The molecular weight estimated by equilibrium sedimentation was approximately 129,000, either in the absence or presence of 6 M guanidine hydrochloride. A slightly higher value of 140,000 determined for the reduced, denatured protein by gel electrophoresis in the presence of sodium dodecyl sulfate and a much higher figure derived from gel filtration are probably due to the glycoprotein nature of the enzyme. Its oligosaccharide content accounted for 26% of the weight calculated from its amino acid and carbohydrate composition. The estimated content of sugar residues per mole was: galactose, 57; N-acetylglucosamine, 53; mannose, 43; N-acetylneuraminic acid, 19; and fucose, 4. Threonine and alanine were identified, respectively, as NH2-terminal and COOH-terminal residues by the dansylation procedure and by digestion with carboxypeptidase A. The enzyme was found to contain approximately 1 g atom of zinc per mol. Km values for hydrolysis of hippurylhistidylleucine and angiotensin I were 2.3 and 0.07 mM, and the corresponding turnover numbers were 15,430 and 792 mol/min/mol at 37 degrees. Bradykinin was also a substrate, and release of its COOH-terminal dipeptide, Phe-Arg, was catalyzed at a comparable rate to that of His-Leu from the COOH terminus of angiotensin I. Enzyme activity required the presence of chloride ions and was inhibited by EDTA and by low concentrations of Bothrops bradykinin-potentiating peptides. In addition, hydrolysis of hippurylhistidylleucine was inhibited competitively by other defined peptides, including di- and tripeptides, which were not substrates.
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PMID:Pulmonary angiotensin-converting enzyme. Structural and catalytic properties. 16 57

Several arginine-rich cationic proteins previously isolated from granules of leukemic myeloid cells have been found to reside primarily in human eosinophil leukocytes. The major component has a molecular weight of 21,000 and it contains approximately 2.6 moles of zinc per mole of protein. Velocity centrifugation of cytoplasm from leukocytes of patients with marked eosinophilia showed that this group of proteins is packaged in the crystalloid-containing large eosinophil granules. Approximately 30% of the protein content of eosinophil granules belonged to this group of cationic proteins. Bactericidal or esterolytic activities of the cationic proteins were not detected, nor did they inhibit guinea pig anaphylatoxin or histamine-induced contraction. The basic protein previously demonstrated in guinea pig eosinophils may be analogous to the group of basic proteins of human eosinophils but great differences are found for molecular weight and amino acid composition.
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PMID:Arginine-rich cationic proteins of human eosinophil granules: comparison of the constituents of eosinophilic and neutrophilic leukocytes. 19 10


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