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)

Polyphosphatase (polyphosphate-phosphohydrolase) has been isolated from mycelium of Neurospora crassa and purified to homogenous state. The enzyme is shown to be strictly specific to high molecular weight inorganic polyphosphates. Km for phosphate in polymeric form is 6.8-10(-4) M. The molecular weight of this enzyme is 50 000 +/- 3000. To display its activity polyphosphatase requires the presence of bivalent cations of some metals, Mg2+ ions being the best activator with Co2+, Mn2+ and Fe2+ ions-slightly less effective.
Mol Biol (Mosk)
PMID:[Isolation and properties of polyphosphatase of Neurospora crassa]. 0 61

We have studied the isocitrate dehydrogenase of Tetrahymena pyriformis. This enzyme is able to utilize both NAD and NADP, but kinetic studies suggest that the enzymatic activity with NAD is not of physiological signifance. Some of the factors that might regualte the NADP-dependent isocitrate dehydrogenase were also studied. This enzyme has an absolute requirement for divalent cations; Mg,+ and Mn2+ will serve as cofactors but the latter is more effective than the former. It is known that this enzyme is subject to a concerted inhibition by oxaloacetate and glyoxylate. Either glyoxylate or oxaloacetate alone also are capable of inhibiting the enzyme although higher concentrations are required. We have found concerted inhibition also for the NAD-dependent isocitrate dehydrogenase from rat liver and yeast. The activity of the Tetrahymena pyriformis enzyme is inhibited by NADPH. This inhibition is competitive with NADP. The Ki and Km values are, respectively, 20 micrometers and 18 micrometers.
Mol Cell Biochem 1977 Oct 07
PMID:Isocitrate dehydrogenase of Tetrahymena pyriformis. 2 34

The relationship between solubilized hormone-binding sites and adenylate cyclase was examined in detergent extracts of particulate testis and ovarian fractions. Both basal and fluoride-stimulated activities of the particulate enzyme were markedly increased in the presence of detergents, and about 60% of the enzyme activity was recovered as the soluble form in the 300,000 g supernatant. Enhancement of adenylate cyclase activity was more marked with Lubrol PX and WX than with Triton X-100, and the highest recovery and activation of adenylate cyclase were obtained with 0.5% Lubrol PX. The particulate and solubilized testicular enzymes were more active in the presence of Mn2+, and the detergent-extracted soluble ovarian cyclase showed a small and inconstant response to gonadotropin. Fractionation of Lubrol-solubilized testis and ovarian preparations on Sepharose 6B showed two peaks of free gonadotropin receptors. The binding activity eluted with Kav of 0.32 corresponded to the receptor sites previously characterized in detergent-solubilized gonadal particles, and was coincident with the elution profile of adenylate cyclase activity. An additional peak of binding activity with Kav of 0.56 was not accompanied by detectable adenylate cyclase activity. These observations suggest that the peak of larger molecular size could represent dissociated receptors or binding sites which were not coupled to adenylate cyclase.
Mol Cell Endocrinol 1977 Feb
PMID:Properties of detergent-solubilized adenylate cyclase and gonadotropin receptors of testis and ovary. 19 64

The change of longitudinal proton relaxation rate, 1/T1, in the native and shocked chloroplasts, PS2 chloroplasts' particles and exogenous complexes Mn2+--PPCI (pigment--protein complex of PSI), Mn2+--PPCII in the presence of the PS2 donors and acceptors and at different pH change were studied. It has been shown that 1/T1 increases in chloroplasts and PS2 particles in the presence of the PS2 donors and decreases in the presence of the acceptors in contrast to untreated preparations. The 1/T1 change of exogenous complexes is not specific. The results suggest that the manganese pool of the chloroplasts PS2 may be the main factor responsible for the chloroplasts' proton relaxation rate. The change of the manganese valency in the presence of donors and of acceptors may result in changing 1/T1.
Mol Biol (Mosk)
PMID:[Effect of oxidizing and reducing agents on the rate of water proton relaxation in the chloroplasts of beans and particles of photosystem 2]. 20 63

A method for investigating the microstruct and dynamics of biological systems by means of triplet-excited molecules is suggested. The method is based on the phenomenon of triplet excitation disactivation by exchange-resonance triplet-triplet energy transfer to the acceptor or by intercombination conversion induced by interaction of an excited molecule with a paramagnetic center. The disactivation efficiency was measured by registrating the phosphorescense decay kinetics. The interaction of the triplet label eosin isothiocyanate, covalently coupled with albumine, lysozyme, sarcoplasmic reticulum membrane and Ca-Mg-dependent sarcoplasmic reticulum ATPase, with O2, the stable nitroxide radicals and ions of Mn2+ was investigated to analyse the potentialities of this method. As a model system the eosin phosphorescence quenching by the same quenchers in glycerine-aguaous solutions was studied. The method permits to investigate the microviscosity and microstructure of biological objects in the label attached region on interaction of the label with a sound-quencher with constants being 10(4) divided by 10(9) M-1 sec-1 and to measure the lateral diffusion of molecules in highly viscosity media (10 divided by 10(5) santypuas).
Mol Biol (Mosk)
PMID:[Investigation of the microstructure of biological systems by triplet label]. 22 37

The phosphorylation of proteins in the synaptic plasma membrane is a rather slow reaction taking several minutes to saturate all the phosphate acceptor sites. (The time for half the protein bound phosphate groups to turnover is about 1 min). A divalent cation is needed as a cofactor for the reaction. At high (0.5 mM) ATP concentrations Mg2+ is more effective than Mn2+ but at low (10 microM) ATP concentrations the reverse is the case. Zn2+ and Ca2+ support very little phosphorylation.
Mol Cell Biochem 1979 Oct 15
PMID:The time course of the phosphorylation of proteins in the synaptic plasma membrane and the effect of certain cations. 22 75

A medium was found in which manganese efficiently induces erythromycin-resistant mitochondrial mutations, and which is suitable for measuring Mn2+ uptake and the labelling of DNA (fig. 1). Mn2+ uptake is stimulated by glucose and slowed down by cycloheximide (Fig 2). Mg2+ competes with Mn2+ uptake much stronger than does Zn2+ (Fig. 3). All of the conditions which favour Mn2+ uptake also favour induction of erythromycin-resistant mutations (Tables 3, 4). Mn2+ strongly inhibits protein synthesis (Table 1). Nuclear DNA replication is also strongly inhibited by this cation, while mitochondrial DNA replication is only weakly inhibited during the first 3 h of labelling, but there is small if any increase of the label incorporation between the 3rd 6th h of labelling (Table 2). The relation between label incorporation into mitDNA and mutation induction by manganese is not straightforward (Table 5). From among 11 divalent cations tested, only Mn2+ was capable of inducing mitochondrial erythromycin-resistant mutations (Table 6).
Mol Gen Genet 1977 Feb 28
PMID:Manganese mutagenesis in yeast. VI. Mn2+ uptake, mitDNA replication and ER induction: comparison with other divalent cations. 32 69

Enhancement of the nuclear relaxation rates by manganese has been used to derive manganese--purine-ring distances in the activation site of methionyl-tRNA synthetase. This is possible with the help of an abortive complex between the enzyme, methionine, adenosine, pyrophosphate and manganese which simulates an intermediate species of the activation reaction. It is found that the distances between the manganese ion and the purine ring are too high (greater than 0.8 nm) to allow interaction between them. Thus, metal-purine interaction is involved neither in the catalytic mechanism nor in the stabilization of abortive synergistic complexes [S. Blanquet, G. Fayat and J. P. Waller (1975) J. Mol. Biol. 94, 1-15].
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PMID:Methionyl-tRNA synthetase from Escherichia coli. Absence of interaction between the metal ion and the purine ring of ATP in the L-methionine activation site. 34 71

Phenotypic "revertants" of a drug resistant strain of Saccharomyces cerevisiae were induced by mutgenesis with manganese. Several of these drug sensitive mutants have been shown to result from mutations in the nuclear genome that cause phenotypic modification (suppression) of the mitochondrially-determined drug resistant genotype. Four mutants carrying a single recessive nuclear gene capable of modifying mitochondrial chloramphenicol resistance are described; these may be assigned to three complementation groups. Chloramphenicol resistant mutants mapping at five separate mitochondrial loci are described. At least two of the nuclear genes cause modification of mitochondrial chloramphenicol resistance determined by mutations at three of these loci, but the other two loci are apparently non-suppressible by these nuclear alleles. This indicates that these modifiers do not act by causing a general decrease in cellular or mitochondrial permeability to the drug. A single dominant nuclear modifier of mitochondrial paromomycin resistance has been identified. It is non-allelic to and does not interact with the genes modifying mitochondrial chloramphenicol resistance.
Mol Gen Genet 1979 Jan 02
PMID:Suppression of mitochondrially-determined resistance to chloramphenicol and paromomycin by nuclear genes in Saccharomyces cerevisiae. 36 91

We have studied the effects of Co2+ and Mn2+ ions on the low-field nuclear magnetic resonance (NMR) spectra of pure class 1 transfer ribonucleic acid (tRNA) species. With 1.2 mM tRNA in the presence of 15 mM MgCl2 discrete paramagnetic effects were observed for Co2+ at concentrations in the range 0.02--0.1 mM and for Mn2+ in the range 0.002--0.01 mM, indicating fast exchange of these cations with tRNA. Both of these cations paramagnetically relax the s4U8--A14 resonance as well as other resonances from proximal base pairs. The Co2+ site appears to be the same site on G15 which was observed crystallographically [Jack, A., Ladner, J. E., Rhodes, D., Brown, R. S., & Klug, A. (1977) J. Mol. Biol. 111, 315-328]; the initially occupied tight Mn2+ site is the cation site involving the phosphate of U8. There are three base pairs within 10 A of both sites, namely, G15--C48, A14--s4U8, and C13--G22; this has led to the assignment of the G15--C48 and C13--G22 resonances in the NMR spectrum [Jack, A., Ladner, J. E., Rhodes, D., Brown, R. S., & Klug, A. (1977) J. Mol. Biol. 111, 315--328; Holbrook, S. R., Sussman, J. L., Warrant, R. W., Church, G. M., & Kim, Sung-Hou (1977) Nucleic Acids Res. 4, 2811--2820; Quigley, G. J., Teeter, M. M., & Rich, A. (1978) Proc. Natl. Acad. Sci. U.S.A. 75, 64--68].
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PMID:Paramagnetic ion effects on the nuclear magnetic resonance spectrum of transfer ribonucleic acid: assignment of the 15--48 tertiary resonance. 38 41


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