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)

Histone kinase activity was purified from human polymorphonuclear leukocytes by ammonium sulphate precipitation of a 180 000 x g supernatant, followed by DEAE-cellulose chromatography and gelfiltration. On DEAE-cellulose cAMP dependent kinase activity eluted in two peaks, I and III, at 1.2 mmho and 6.5 mmho, respectively. Catalytic subunit (C) from both peaks had Mr 33 000, 3.0S. Regulatory subunit (R) from peak I and III both had Mr 33 000 upon gelfiltration, but sedimented at 2.8--3.0S and 3.0--3.2S, respectively. R2 and R4 subunits were identified. The R-C dimer from peak I and III sedimented at 4.8S and (4.8)--5.1S, respectively. The holoenzyme from peak I had Mr 165 000, 6.7S, which suggest a R2C2 structure, while that of peak III sedimented at 6.7S, but eluted at Mr 330 000 (2R2C2) by gelfiltration. The Kmapp for peak I and III enzymes were, respectively: histone IIA 0.5 mg/ml (both forms), ATP 18 microM and 23 microM, and cAMP 5 X 10(-8) M and 6.3 x 10(-8) M. Both enzymes had pH optimum 6.7--6.9 and were equally sensitive to Ca2+, temperature and protein kinase inhibitor. The substrate specificity was histone VS greater than histone IIA = histone VIS greater than casein greater than phosvitin. Peak I enzyme, but not peak III enzyme, was dissociated by histone and high ionic strength and reassociation of R and C subunits were facilitated by ATP-Mg. It is concluded that peak I and III enzymes represent type I and II cAMP dependent protein kinases, respectively. Type I comprises 20--30% of cAMP dependent protein kinase activity and is absent from the 180 000 x g supernatant of gently disrupted cells. Purified catalytic subunit had Kmapp (ATP) 20 microM with rabbit muscle glycogen synthease I as substrates. Synthase I from rabbit muscle and human leukocytes were phosphorylated by catalytic subunit to synthase D (ratio of independence less than 0.07). cAMP independent histone kinase activity eluted in one peak (Peak II) at3 mmho. The enzymatic activity sedimented at 3.4S and eluted from gelfiltration with Mr 78 000. Kmapp for ATP was 78 microM and for histone IIA 0.5 mg/ml. The enzyme was sensitive to temperature, but less sensitive than cAMP dependent protein kinase to Ca2+, and insensitive to protein kinase inhibitor. The substrate specificity was histone IIA greater than histone VS = histone VIS, while casein and phosvitin were poor substrates. Glycogen synthase I was not phosphorylated. The cAMP independent histone kinase activity comprised 15% of the total histone kinase activity in a crude homogenate of leukocytes. Its physiological substrate is unknown.
Mol Cell Biochem 1979 Jul 15
PMID:Purification and properies of cAMP dependent and independent histone kinases from human leukocytes. 22 66

1. The rate of removal from the circulation of an intravenous lactic acid load has been studied in conscious rats, previously subjected either to bilateral nephrectomy or to a sham operation. 2. In rats with normal blood pH, the apparent contribution of the kidneys to removal of the lactic acid load is 30%; less than 12% of the renal contribution is attributable to urinary excretion. 3. In bilaterally nephrectomized rats made acidotic by administration of ammonium chloride, the rate of removal of a half-neutralized lacrtic acid load is progressively decreased with increasing severity of acidosis. No such effect is seen in sham-operated animals. 4. An increase in the ability of the kidney to remove lactate during acidosis compensates for approximately half of the simultaneous fall in the capacity of the remainder of the body for lactate assimilation. 5. Basal blood lactate concentrations fall in the presence of metabolic acidosis.
Clin Sci Mol Med 1975 Feb
PMID:The contribution of the kidney to the removal of a lactic acid load under normal and acidotic conditions in the conscious rat. 23 19

Some similarity is inferred between the reaction or reduced benzyl viologen with undissociated nitrous acid, which is significant at pH values below 7 and that with the undissociated product of nitrite ion and ammonium sulphate; presumably ammonium nitrite. This would explain why the presence of ammonium sulphate appreciably offsets the effects of decreasing pH and also the exponential relationship between rate of nitrite loss and ammonium sulphate concentration. There are other features of the reaction which cannot be explained at present, especially with regard to the degree of reduction of benzyl viologen. It is nevertheless apparent that a complex non-enzymic reaction yielding several products occurs when ammonium sulphate is present and that the presence of likely residual quantities after its use in enzyme purification may cause serious errors in enzyme assay.
Mol Cell Biochem 1975 Feb 28
PMID:The non-enzymic reduction of nitrite by benzyl viologen (free-radical) in the presence and absence of ammonium sulphate. 23 35

1. Ammonia and urea transport across the colonic mucosa was studied by a perfusion technique in four subjects with colonic exclusion for chronic hepatic encephalopathy. 2. Reduction of luminal pH inhibited net and unidirectional transport of ammonia from lumen to plasma, but net absorption from high luminal concentrations persisted at low pH. 3. Neither addition of urea to the perfusate nor intravenous infusion of urea produced a consistent increase in the colonic excretion of ammonia when ammonia-free solutions were perfused. 4. In one subject intravenous infusion of (15N)-ammonium chloride produced rapid labelling of colonic effluent ammonia and within 60 min the specific enrichments of ammonia in effluent and in arterial plasma were approximately equal. 5. During perfusion of nitrogen-free solutions, only small amounts of urea appeared in the effluent, suggesing limited permeability of the colonic mucosa to urea. 6. These results are discussed in relation to the equilibration of ammonia across the colonic mucosa by both ionic and non-ionic diffusion. The lack of evidence of 'juxtamucosal' (as opposed to luminal) ureolysis is in contrast to other observations on the intact colon. The possible reasons for and implications of this discrepancy are discussed.
Clin Sci Mol Med 1975 Apr
PMID:Ammonia and urea transport by the excluded human colon. 23 10

A simple method is described for the isolation of crystalline pyruvate kinase from human skeletal muscle. The enzyme was purified by ammonium sulfate fractionation, heat treatment and crystallization. Two crystal forms of pyruvate kinase differing in solubility but not in specific activity were found. The homogenous enzyme preparations in triethanolamine buffer, pH 7.6 reveal at 25 degrees a specific activity of 245 U per mg protein, and of 340 U/mg in potassium phosphate buffer (50 mM). The enzyme is activated by inorganic phosphate and fructosediphosphate to the same extent, and inhibited non competetively by ammonium ion. The molecular weight as measured by gel filtration is 220,000 daltons and the enzyme molecule is composed of 4 subunits.
Mol Cell Biochem 1975 Mar 27
PMID:Pyruvate kinase from human skeletal muscle. 23 10

Measurements of association constants (Ka) of specific [14C]Phe-tRNAPhe with a 30S..poly(U) complex revealed that values of these constants vary from 0.5.10(7) up to 1.5.10(8) M--1 when different 30S subunit preparations were used at the same medium conditions (20 mM Mg2+, 200 mM NH4, 0 degrees C). Analysis of these data showed that the higher the rotor speeds were used during separation of 70S ribosomes into subunits, the less Ka values were measured. In special experiments on sedimentation of pure 30S subunits at different rotor speeds it was found that the decrease of Ka values was caused due to the additional reversible dissocation of ribosomal proteins from 30S subunits at high (the order of 100 000.g) centrifugal fields. As a possible mechanism of such dissociation we suggest the influence of high hydrostatic pressure on the association constants of S-proteins with 30S subunits. Data presented in this paper demonstrate that at least one of the reasons for the physical and functional heterogeneity of 30S subunits in vitro derives from the application of high centrifugal fields during isolation of ribosomal subunits.
Mol Biol (Mosk)
PMID:[Nature of the heterogeneity of 30S ribosomal subparticles in vitro. I. Effect of large centrifugal fields during 30S subparticle isolation on their capacity for codon-dependent tRNA binding]. 24 37

The conformational motilities of three regions of the sperm whale myoglobin molecule and of an isolated peptide of myoglobin have been examined by measuring the equilibrium constant for the native equilibrium nonnative transition. The immunological approach of Furie et al. (Furie, B., Schechter, A.N., Sachs D., and Anfinsen, C.B. (1975), J. Mol. Biol.92, 497-506) was used with convenient modifications. Antibodies specific to the nonnative conformations were used in assaying for competition between the radioactively labeled peptide and native myoglobin. Labeling was by 125I iodination of the peptide or its 3-(4-hydroxyphenyl)propionyl derivative, and separation of the immune complex from the free peptide was either by ammonium sulfate precipitation or by centrifugation of the antibodies immobilized on Agarose beads. For the antigenic regions of the sequence (1-55), the measured conformational equilibrium constant was 840 +/- 200 at 22 degrees C; the value for the C-terminal region (132-153) was 280 +/- 120 at 25 degrees C, while that for the region (66-76) adjacent to the heme group was greater than 2.5 x 10(6). Measurements on the isolated peptide (132-153) indicated that 1% of the molecules adopt native-type folding in aqueous solution at 36 degrees C.
 ...
PMID:Immunological measurements of conformational motility in regions of the myoglobin molecule. 31 22

The replication cycle of the small resistance plasmid RSF1030 can be divided into two stages with different enzyme requirements: (1) Synthesis of early replicative intermediates containing 7 S DNA catalyzed by DNA polymerase I in the absence of functional dnaZ protein, and (2) replication of early intermediates requiring DNA polymerase III holenzyme (including the dnaZ protein). Early intermediate DNA synthesized in a dnaZ extract can be converted to fully replicated plasmid molecules upon addition to a replication enzyme fraction prepared by ammonium sulfate fractionation of polA I extracts. The first-stage reaction is sensitive to rifampicin, novobiocin, and oxolinic acid, but insensitive to arabinosylcytosine triphosphate (aCTP). Addition of aCTP interferes with the second-stage reaction resulting in the accumulation of late replicative intermediates.
Mol Gen Genet 1977 Nov 04
PMID:Replication of the ampicillin resistance plasmid RSF1030 in extracts of Escherichia coli: separation of the replication cycle into early and late stages. 34 Aug 89

A study has been made of the effects of a casamino acids shift-up on a prototrophic strain of yeast growing under conditions of ammonium repression. The shift-up produced an increase in growth rate some 120 min after the addition of amino acids to the medium. This growth rate increase was slightly preceded by an increase in the rate of accumulation of DNA. In contrast, the rate of accumulation of protein increased immediately and that of RNA 15-20 min after the shift. RNA was initially accumulated at a rate greater than that required to sustain the new steady state. This was shown to be due to an increase in the rate of synthesis of the rRNA species derived from the 35S precursor. The rate of synthesis of 5S rRNA and of tRNA increased much later and to a lesser extent than that of the 35S derived species. The implications of these results for general theories of regulation of RNA synthesis are discussed.
Mol Gen Genet 1977 Dec 30
PMID:The regulation of RNA synthesis in yeast II: Amino acids shift-up experiments. 34 Sep 32

In Aspergillus nidulans expression of the gabA gene, the probable structural gene for the gamma-amino-n-butyrate (GABA) permease, is controlled by induction, via the intA gene, ammonium repression, mediated by the areA gene, and probably carbon catabolite repression. Regulatory mutations, tightly linked to gabA, were selected by reverting an areAr-2 strain on GABA as nitrogen source. These mutations, gabI-1, gabI-2, and gabI-3 result in increased gabA expression and are cis-dominant in their effects on the gabA gene. Mapping data show that the regulatory mutations map on one side of all gabA- alleles tested.
Mol Gen Genet 1979 Jan 16
PMID:Cis-dominant regulatory mutations affecting the expression of GABA permease in Aspergillus nidulans. 37 1


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