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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The protein spin-echo decay and recovery of longitudinal magnetization were studied in seven globular proteins: cytochrome C, ribonuclease, lysozyme, DNA, hemoglobin, serum albumin and gamma-globulin in D2O solutions. For comparison the Tobacco mosaic virus (TMV) protons in D2O solutions were also investigated. The spin-echo decay of all 7 proteins can be separated into three components: a slowly decaying component with an amplitude of about 10% of the amplitude of the total signal, intermediately and fastly decaying components, the two latter being comparable in amplitudes. Longitudinal relaxation is more simple in character. The value of T2 of the protons responsible for the fastly decaying components in linearly dependent on the molecular weight of the protein, a fact indicating that the regions of the proteins with a "rigid" structure can be responsible for this component. The intermediate component, whose contribution increases with temperature, was ascribed to the mobile regions of the protein, and the slowly decaying component to the mobile protein side chains. Weak dependence of T1 on the protein molecular weight and some other obtained data give additional evidence for the presence of motion within macromolecules. The peculiarities of this motion is in good correspondence with the notion about the existence of the segmental motion of the polypeptide chain (conformational mobility of the protein). In contrast to proteins the spin-echo decay of TMV lacked the slow component and the "solid" echo signal was observed which indicates the existence of a "rigid" structure in the macromolecules of the virus.
Mol Biol (Mosk)
PMID:[Study of the conformational mobility of globular proteins by pulse methods of NMR]. 20 75

Methods by which the intracellular enzymes deoxyribonuclease, ribonuclease and protease can be assayed in whole colonies of Saccharomyces cerevisiae on agar plates are described. A search for mutants deficient in deoxyribonuclease has been carried out. Two types of mutant are described. One apparently fails to produce deoxyribonuclease, ribonuclease or protease on agar plates and the other apparently fails to produce deoxyribonuclease and ribonuclease.
Mol Gen Genet 1977 Apr 29
PMID:The use of a novel plate assay in a search for yeast mutants defective in deoxyribonucleases. 32 78

Fourteen mammalian pancreatic ribonucleases of known amino acid sequence were compared by 1 or more of 3 different immunological methods: standard quantitative micro-complement fixation, spot-plate micro-complement fixation, and inhibition of phage inactivation. It was found that, while the results obtained by the 3 techniques were correlated with one another, the standard micro-complement fixation procedure was most versatile, economical of materials, and easiest to execute. The standard MC'F technique was more sensitive than the spot-plate technique to differences in amino acid sequence. The inhibition of phage inactivation method was more sensitive than the standard method for measuring differences among closely related RNases but proved impractical for amino acid differences over 15%; the MC'F method could be extended to at least 30% sequence differences. The standard method, moreover, readily detected the single amino acid difference between dromedary and camel RNases. A linear relationship was found between immunological distance (y) in the MC'F test and percent sequence difference (x) which fit the equation y = 7x. The strength of the correlation between immunological distance and percent sequence difference is consistent with the proposal that a large fraction of the evolutionary substitutions of amino acids in ribonuclease are immunologically detectable. This could be explained either by a multideterminant hypothesis or by a pauci-determinant hypothesis which says that substitutions occurring outside determinants produce small conformational changes influencing determinant reactivity.
J Mol Evol 1978 Feb 21
PMID:Comparison of various immunological methods for distinguishing among mammalian pancreatic ribonucleases of known amino acid sequence. 34 95

Cellular lysates with very low total ribonuclease activities are obtained by lysis of Saccharomyces cerevisiae VY1160 osmotic sensitive mutant cells in 1% sorbitol solution. These lysates could be used for isolation of intact polysomes and messenger RNA molecules, or for studying of specific ribonucleases.
Mol Gen Genet 1979 Aug
PMID:Low ribonuclease activity in cellular lysates of osmotic sensitive Saccharomyces cerevisiae mutants. 39 Mar 2

The 16S ribosomal RNAs from two species of methanogenic bacteria, the mesophile Methanobacterium ruminantium and the thermophile Methanobacterium thermoautotrophicum, have been characterized in terms of the oligonucleotides produced by digestion with T1 ribonuclease. These two organisms are found to be sufficiently related that they can be considered members of the same genus or family. However, they bear only slight resemblance to "typical" Procaryotic genera; such as Escherichia, Bacillus and Anacystis. The divergence of the methanogenic bacteria from other bacteria may be the most ancient phylogenetic event yet detected--antedating considerably the divergence of the blue green algal line for example, from the main bacterial line.
J Mol Evol 1977 Aug 05
PMID:An ancient divergence among the bacteria. 40 2

Cell-free protein synthesizing systems were prepared from the livers of chick embryos at selected ages and the characteristics of individual fractions were compared. While polysomes showed decreasing size with older embryos, isolated polysomes did not differ significantly in amino acid incorporating activity when assayed with standard cell sap. When assayed with standard polysomes, cell sap activity decreased with increasing developmental age whether incorporation was measured using (3H)lysine, (3H)leucine, or [3H]aminoacyl-tRNA. Free amino acid concentrations in the cell sap showed reproducidble independent variation during development which was taken into consideration in calculating net amino acid incorporation. A larger increase in ribonuclease activity was observed during development; however, nuclease inhibitor activity was absent before day 15 but increased thereafter. Aminoacyl-tRNA sythetase activity did not vary significantly. It is proposed that the observed changes in the rate of cell-free protein synthesis result not only from increasing ribonuclease activity with increasing developmental age but also from changes in the activity of other soluble factors.
Mol Cell Biochem 1979 Apr 02
PMID:Polymorphism in fowl serum albumin. VI. Changes in in vitro protein synthesizing activity in developing embryonic fowl liver. 46 Jan 76

The size distribution of newly synthesized and old poly(A) sequences on transcripts of the giant tissue specific puffs, Balbiani rings in salivary glands of Chironomus tentans has been determined. After labeling with [3H]adenosine, poly(A) containing Balbiani ring RNA(75S RNA) was selectively collected by means of a recently developed technique. This combines electrophoretic fractionation and affinity chromatography in one run by insertion of poly(U) immobilized in glass fiber filters in an agarose gel slab. The majority of short-term labeled poly(A) chains released from poly(A) containing 75S RNA molecules is distributed within a narrow size range migrating as one peak with a mean value of 103 +/- 2 nucleotides, which is probably the initial length of poly(A). The labeling pattern of ribonuclease resistant poly(A) stretches after chase with unlabeled adenosine displays a relatively broad and heterogeneous size spectrum from at least 20 to more than 100 nucleotides. The main peak of labeled adenylate core in newly formed poly(A) containing RNA of non-Balbiani ring origin is dispersed within a broader size range than that of Balbiani ring RNA and possesses an average value of 94 +/- 2 nucleotides. During chase conditions, the relative frequency of occurrence of poly(A) chains of 75S RNA in the size range of 100 nucleotides exhibits a significant decrease in parallel with a rather uniform gain in the size classes between 20--50 nucleotides. However, the results are inconsistent with the existence of an age-dependent shortening of poly(A) chains in the balbiani ring RNA. A significant portion of 75S RNA molecules remain associated with poly(A) segments which are essentially of original size even after 21 hr in the presence of unlabeled adenosine. This finding provides support for the possibility that the initiation of the poly(A) shortening in 75S RNA is a stochastic process.
Mol Biol Rep 1979 May 31
PMID:The size distribution of poly(A) in newly synthesized and old Balbiani ring RNA. 46 Jan 78

Proteins of polyribosome-bound informosomes of germinating wheat embryos were studied by electrophoresis in polyacrylamide gel in presence of sodium dodecyl sulfate. liberation of informosomal proteins was achieved by mild ribonuclease treatment of polyribosomes. It was shown, that proteins of informosomes associated with polyribosomes contain polypeptides with molecular weights of 86 000, 75 000, 72 000, 66 000, 52 000 and 34 000. The milecular weights of two most prominent proteins were 86 000 and 52 000. The treatment of polyribosomes with 0.5 M KCl resulted in the loss of large part of informosomal proteins, which are revealed in the KCl-wash.
Mol Biol (Mosk)
PMID:[Proteins of polyribosome-bound informosome of germinating wheat embryos]. 50 61

Groups of adult rats were injected with either saline or pentagastrin (500 microgramg/kg) for 14 days. The capacity of the gastric mucosal ribosomes to synthesize endogenous and exogenous mRNA-directed protein in a cell-free system was then investigated. Polyribosomal profiles were also analysed on sucrose gradients. The endogenous mRNA-directed incorporation of 14C-labelled amino acids into protein by the gastric mucosal ribosomes from the pentagrastrin-injected rats was found to be considerably greater than that of the control. In the presence of exogenous mRNA (poly-U) the polyribosomes as well as the endogenous mRNA-free ribosomes (run-off ribosomes) from the pentagastrin-treated group showed 86% and 136% increment in [14C]-phenylalanie incorporation as compared to the corresponding control preparation. The ribosomal ribonuclease activity between the groups was found to be the same. The results of the present investigation indicate that an enhancement in the translational capacity of the ribosomes is in part responsible for stimulation of gastric mucosal protein synthesis after chronic administration of pentagastrin.
Mol Cell Endocrinol
PMID:Chronic administration of pentagastrin: effect on gastric mucosal protein synthesis in rats. 68 Mar 38

The 16S ribosomal RNA (30S subunit) of Rhodopseudomonas spheroides has been characterized in terms of T1 ribonuclease digestion products. This "fingerprint" ultimately permits the placement of R. spheroides into a detailed procaryotic phylogenetic tree. Given the number of major procaryotic lines that have been characterized in these terms to date, one can tentatively place the Athiorhodaceae closer to the Vibrio-Enteric group than to the Bacillaceae or Cyanophyta.
J Mol Evol 1975 Jun 09
PMID:Procaryote phylogeny IV: concerning the phylogenetic status of a photosynthetic bacterium. 80 94


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