Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A series of amino acid reagents was tested on the glucose-6-P dependent D, and independent I forms of glycogen synthase (UDPG: glycogen alpha-4-glucosyltransferase, EC 2.4.I. II) from rabbit skeletal muscle, at two levels of purification. Whereas blocking of aliphatic hydroxyl groups did not result in any inhibition of the enzyme(s), blocking of aromatic hydroxyl groups resulted in a gradual and complete inhibition. Under the stated assay conditions both forms of the enzyme were similarly affected in terms of activity, but the tyrosines of the D form were found to react more readily chemically. Tyrosine appears to be "essential" for catalysis. No desensitization to the allosteric modulator glucose-6-P was detected.
Mol Cell Biochem 1975 Jan 31
PMID:Effects of group-selective reagents on rabbit muscle glycogen synthase. 80 91

The effect of cortisone administration on the rates of muscle protein breakdown and synthesis has been studied in the rat extensor digitorum longus muscle. Cortisone acetate (100 mg/kg body weight/day) was administered intraperitoneally for 1--3 days. Muscle wieght and protein content were significantly reduced by cortisone administration. Rates of protein breakdown were measured by tyrosine release from the isolated muscle into the intracellular pool and medium during a 2-h incubation with cycloheximide to block protein synthesis. Rates of protein synthesis were assayed by [14C]tyrosine incorporation into protein of the isolated muscle during a 2-h incubation. Cortisone administration inhibited significantly the rate of protein synthesis after 1--3 days treatment and also reduced significantly the rate of protein breakdown per muscle after 3 days treatment. The synthesis of myofibrillar and soluble proteins was affected to the same extent. These results strongly suggest that the effect of cortisone administration on muscle protein is mainly through its inhibition of protein synthesis rather than through an acceleration of protein breakdown.
Mol Cell Endocrinol 1977 Jan
PMID:The effect of cortisone on protein breakdown and synthesis in rat skeletal muscle. 83 61

1. Subcutaneous injection of adrenaline into normal male volunteer subjects caused large increases of plasma non-esterified fatty acids and free tryptophan, but plasma total tryptophan fell considerably. Therefore increases of the percentage of plasma tryptophan in the free state were more marked than absolute increases of free tryptophan. 2. Plasma tyrosine fell slightly and plasma phenylalanine and cortisol were unaffected. 3. It is suggested that catecholamine release could lead to abnormalities of tryptophan disposition in stress and psychiatric illness.
Clin Sci Mol Med 1977 Sep
PMID:Effects of adrenaline injection on human plasma tryptophan and non-esterified fatty acids. 91 45

Holo and apoenzyme of aspartate aminotransferase from beef kidney are 80% inactivated by photoxidation in the presence of 2 X 10(-6) M tetraiodofluroescein with the modification of two histidine residues per enzyme protomer. At a higher concentration (1 X 10(-5) M) a tyrosine residue is also modified. The keto substrates, ketoglutarate and oxalacetate, protect the enzyme from photoxidation. Diethylpyrocarbonate modifies three histidine residues per enzyme protomer and reduces the activity only 10%. These results suggest that the two histidine residues photoxidized through the sensitizer, are located in the active site of the enzyme, at least one of these appears to be involved in ketosubstrate binding. The other three histidines modified by diethylpyrocarbonate are likely located on the enzyme surface and are not involved in the catalytic activity of the enzyme.
Mol Cell Biochem 1976 Jun 15
PMID:Chemical modifications of histidine residues in cytoplasmic asparate aminotransferase from beef kidney. 94 May 48

Adenylyl-(5'leads to N)-amino acids containing as amino components, methyl esters of D-, L- and DL-phenylalanine, D-, L- and DL-tyrosine, and D-, L- and DL-tryptophan have been investigated by proton magnetic resonance (PMR) spectroscopy and circular dichroism (CD). The temperature and pD dependences of proton chemical shifts of these compounds have been studied. These data, together with the magnitudes of the upfield chemical shifts of the PMR signals of adenine and aromatic amino acids residues in adenylyl-(5'leads to N)-amino acids, have enabled us to construct conformational models of these compounds. The proposed conformation has been substantiated by the CD results. It is shown that in adenylyl-(5'leads to N)-amino acids the planes of adenine and amino acid aromatic moieties are roughly parallel. The aromatic rings of phenylalanine and tyrosine are localized approximately above the centre of adenine. In adenylyl-(5'leads to N)-D, -(L)-tryptophan, the six-membered rings of the indole overlaps the five-membraned ring of adenine indole partially overlaps the six-membered ring of adenine. A difference in the non-covalent interactions of D- and L-amino acids with nucleotides has been revealed. The mutual localization of the aromatic systems of AMP and the amino acids and also the positions of -OCH3 group with respect to the centre of the amino acid aromatic moiety differs in the series of the studied nucleotide derivatives of D- and L-amino acids.
Mol Biol (Mosk)
PMID:[The secondary structure of amides of adenylic acid containing D- and L-aromatic amino acids]. 94 May 56

The reaction of iodine with aromatic residues of hen egg white lysozyme is examined by means of natural abundance 13C nuclear magnetic resonance spectroscopy. In the unfractionated product of the reaction at PH 5.5 (with I2/lysozyme molar ratios of 0.5, 1.0, and 2.5), the only detectably modified aromatic residues are Trp-108 and either Tyr-20 or Tyr-23 (probably the latter). The rates of reaction at the two sites are similar. The extents of modification (at each site) are approximately 25%, 50%, and approximately greater than 80% for I2/lysozyme molar ratios of 0.5, 1.0, and 2.5, respectively. At pH 4.5, the rates of reaction of both residues are about one-third or less of the rates at pH 5.5. When the reaction is carried out at pH 8.5 (with an I2/lysozyme molar ratio of 1.0), only the tyrosine residue is modified. Resonances observed in the spectra of the modified protein mixtures (but not in the spectrum of intact lysozyme) indicate that the modified Trp-108 residue is not oxindolealanine, but either delta1-hydroxytryptophan or an ester thereof. This result is consistent with previous evidence which indicates that the modified tryptophan is the Glu-35 ester of delta1-hydroxytryptophan-108 (Imoto, T., and Rupley, J.A. (1973) J. Mol. Biol. 80, 657-667; Beddell, C. R., Blake, C. C. F., and Oatley, S. J. (1975) J. Mol. Biol. 97, 643-654). The spectra also indicate that the modified tyrosine residue is predominantly monoiodinated. The spectra of modified protein samples subjected to denaturation with 6M guanidinium chloride for 24 h at 37 degrees (and the renatured) indicate that residue 108 is converted to about equal amounts of the two diastereoisomers of oxindolealanine. However, incubation in 6M guanidinium chloride for 2 h at 25 degrees does not cause measurable hydrolysis of the Glu-35 ester of delta1-hydroxytryptophan-108.
 ...
PMID:Studies of chemical modifications of proteins by carbon 13 neuclear magnetic resonance spectroscopy. Reaction of hen egg white lysozyme with iodine. 98 24

Fe(III), Cu(II), Co(III), and Mn(III) complexes of ovo- and human serum transferrins show resonance enhanced Raman bands near 1600, 1500, 1270, and 1170 cm-1 upon excitation with laser frequencies which fall within the visible absorption bands of those metalloproteins. Comparison of the visible absorption and resonance Raman spectra of the Cu(II)-transferrin complexes with those for the Cu(II) model compound, bis(2,4,6-trichlorophenolato)diimidazolecopper(II) monohydrate, indicates that the resonance Raman bands are due to enhancement of phenolic vibrational modes. For the model (Cu(II) compound, a normal coordinate analysis was used to aid our assignment of the observed resonance bands at 1562, 1463, 1311, and 1122 cm-1 to A1 vibrational modes of the 2,4,6-trichlorophenolato moiety. These assignments are consistent with those made for Cu(II)-transferrins. The latter assignments were based upon calculated A1 frequencies for p-methylphenol (Cummings, D.L., and Wood, J.L. (1974), J. Mol. Struct. 20, 1). The wavelength shifts in the resonance bands for the model compound from those for Cu(II)-transferrins are due to the influence of the chloro substituents on the planar vibrations of phenol. These results clearly identify tyrosine as a ligand in copper binding to transferrins.
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PMID:Resonance Raman spectra of iron(III)-, copper(II)-, cobalt(III)-, and manganese(III)-transferrins and of bis(2,4,6-trichlorophenolato)diimidazolecopper(II) monohydrate, a possible model for copper(II) binding to transferrins. 99 Feb 53

The kinetics of nitration of tyrosine residues in histones F1 and F2a1 by tetranitromethane has been investigated. At low ionic strength and 30-fold molar excess of nitrating agent the nitration reaction results in fast modification of all tyrosine residues in both histones. At the same time the rates of modification of different tyrosine residues in histone F2a1 are not identical and markedly exceed the rate of N-Ac-OEt-Tyr nitration in a model system. The increase of reaction mixture ionic strength causes an increase of modification rates. The differential UV-absorption spectra of histone F1 obtained by temperature perturbation show an abnormal positive characteristic maximum at 286.8 nm. Analysis of the dependence of nitration rates of tyrosine residues in histones in saline solutions upon the ionic strength and of difference UV-absorption spectra of histones leads to a conclusion that there are specific interactions of definite parts of histone polypeptide chains. These interactions may arise from aggregation of histone molecules.
Mol Biol (Mosk)
PMID:[Tyrosine residues in histones. Kinetics of histones F1 and F2A1 nitration by tetranitromethane]. 105 46

Equilibrium constants (K) of the complex formation of adenosine-5'-phosphate with phenylalanine (27 l/mol) and tryptophan (67 l/mol) in water (D2O, pD 9.9) have been determined. The comparison of the equilibrium constant values allowed to find the sequence of probabilities of the approach of aromatic amino acids to adenosine-5'-phosphate (tryptophan greater than tyrosine greater than phenylalanine). It has been shown that the dependence of lg K on l/T in the system phenylalanine-adenosine-5'-phosphate is non-linear. The ranges of the positive values of enthalpy (deltaH) and entropy (deltaS) changes of the complex phenylalanine-adenosine-5'-phosphate formation in the temperature interval 28-65 degrees have been found (deltaH = 0.2-1.5 kcal/mol, delta S = 14-50 e.u.). The conclusion about the hydrophobic interaction of aromatic cycles of nucleotide and amino acids has been deduced from the received data.
Mol Biol (Mosk)
PMID:[Intermolecular interaction of adenosine-5'-phosphate with phenylalanine and tryptophan by nuclear magnetic resonance]. 105 79

1. A peripheral inhibitor of L-aromatic amino acid decarboxylase, carbidopa [(-)-L-alpha-hydrazino-3,4-dihydroxy-alpha-methylbenzenepropanoic acid monohydrate], at doses up to 25 mg/kg intraperitoneally or 30 mg/kg orally had no effect on directly recorded arterial pressure of spontaneously hypertensive rats derived from the Wistar/Okamoto strain. It enhanced, however, the anti-hypertensive effects of methydopa, hydrallazine, guanethidine and clonidine, and, to a lesser extent, reserpine and hydrochlorothiazide. The mechanism of this enhancement is presently unkonwn, but biochemical studies support the assumption that carbidopa is likely to reduce sympathetic nervous system activity. 2. The conversion of [3H]tyrosine (given intraperitoneally) to dopa (3,4-dihydroxypheylalanine) and catecholamines was measured in the hearts and adrenals of control rats and animals pretreated with carbidopa (100 mg/kg, intraperitoneally). Carbidopa significantly decreased the accumulation of 3H-labelled catecholamines in both organs and increased their total tyrosine content and the specific radioactivity of tyrosine.
Clin Sci Mol Med Suppl 1976 Dec
PMID:Enhancement of the anti-hypertensive effect of methyldopa and other anti-hypertensive drugs by carbidopa in spontaneously hypertensive rats. 107 55


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