Abstract:
:alpha-Isopropylmalate synthase [3-hydroxy-4-methyl-3-carboxyvalerate 2-oxo-3-methylbutyrate-lyase (CoA-acetylating); EC 4.1.3.12], the enzyme catalyzing the first committed step in leucine biosynthesis, and homocitrate synthase [3-hydroxy-3-carboxyadipate 2-oxoglutarate-lyase (CoA-acetylating); EC 4.1.3.21], the first enzyme in lysine biosynthesis in yeast, are rapidly inactivated in the presence of low concentrations of coenzyme A, a product of both reactions. Closely related compounds like 3-dephospho-coenzyme A or oxidized coenzyme A are almost without effect, as are other sulfhydryl compounds. Citrate (si)-synthase [citrate oxaloacetate-lyase (pro-3S-CH2-COO-minus leads to acetyl-CoA); EC 4.1.3.7] appears to be completely resistant against inactivation by coenzyme A. Inactivated alpha-isopropylmalate and homocitrate synthases can be reactivated by dialysis, but not by adding excess substrate. Protection against coenzyme-A-mediated inactivation is provided by relatively high concentrations of the alpha-ketoacid substrate or the specific end product inhibitor of each of the two enzymes. The coenzyme-A-mediated inactivation of alpha-isopropylmalate synthase has been more closely investigated. It requires the presence of divalent metal ions, with Zn++being most effective. The inactivation does not require molecular oxygen. It occurs in the presence of low concentrations of substrates and is observed in toluene-treated cells. These results, together with evidence that alpha-isopropylmalate synthase and homocitrate synthase are located in the mitochondria, suggest a mechanism by which increasing intra-mitochondrial coenzyme A concentrations might serve as a signal of decreasing acetyl-coenzyme A levels, triggering a temporary inactivation of biosynthetic acetyl-coenzyme A-consuming reactions in order to channel the available acetyl-coenzyme A into the citrate cycle.
journal_name
Proc Natl Acad Sci U S Aauthors
Tracy JW,Kohlhaw GBdoi
10.1073/pnas.72.5.1802keywords:
subject
Has Abstractpub_date
1975-05-01 00:00:00pages
1802-6issue
5eissn
0027-8424issn
1091-6490journal_volume
72pub_type
杂志文章abstract::The effects of phorbol 12-myristate 13-acetate (PMA), a potent activator of protein kinase C, on Na+ influx were investigated in cultured human foreskin fibroblasts (HSWP cells). We report here that in serum-deprived HSWP cells the addition of PMA alone has no significant effect on Na+ influx. However, the addition of...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.82.23.8053
更新日期:1985-12-01 00:00:00
abstract::Polyclonal antibodies reactive with a cleavage site in human proinsulin (HPI) (C-peptide-A-chain junction) have been raised (rabbit, guinea pig) using a synthetic peptide antigen coupled with keyhole limpet hemocyanin. These antisera recognize native HPI and des-31,32-HPI equally well but react 20-50 times less well w...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.17.6184
更新日期:1987-09-01 00:00:00
abstract::The brain contains an astonishing diversity of neurons, each expressing only one set of ion channels out of the billions of potential channel combinations. Simple organizing principles are required for us to make sense of this abundance of possibilities and wealth of related data. We suggest that energy minimization s...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0914886107
更新日期:2010-07-06 00:00:00
abstract::A pure population of mast cells was obtained after 14 days of culturing mouse bone marrow cells in the presence of medium derived from concanavalin A-stimulated mouse spleen cells. The cells were characterized as mast cells by their morphologic appearance and histologic staining, by their histamine content (450 ng per...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.78.4.2559
更新日期:1981-04-01 00:00:00
abstract::Lipid droplets (LDs) are a conserved feature of most organisms. Vertebrate adipocytes have evolved to efficiently store and release lipids for the whole organism from a single droplet. Perilipin 1, the most abundant lipid-coat protein in adipocytes, plays a key role in regulating lipolysis. In other tissues such as li...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1318791111
更新日期:2014-06-24 00:00:00
abstract::Numerous international bodies have advocated the development of strategies to achieve the sustainability of marine environments. Typically, such strategies are based on information from expert groups about causes of degradation and policy options to address them, but these strategies rarely take into account assessed ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1417344111
更新日期:2014-10-21 00:00:00
abstract::Deficiency of acyl CoA:cholesterol acyltransferase 2 (ACAT2) in mice results in a reduction in cholesterol ester synthesis in the small intestine and liver, which in turn limits intestinal cholesterol absorption, hepatic cholesterol gallstone formation, and the accumulation of cholesterol esters in the plasma lipoprot...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0336398100
更新日期:2003-02-04 00:00:00
abstract::Xanthophyll pigments have critical structural and functional roles in the photosynthetic light-harvesting complexes of algae and vascular plants. Genetic dissection of xanthophyll metabolism in the green alga Chlamydomonas reinhardtii revealed functions for specific xanthophylls in the nonradiative dissipation of exce...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.25.14162
更新日期:1997-12-09 00:00:00
abstract::In mammalian females, most genes on one X chromosome are transcriptionally silenced as a result of X chromosome inactivation. Whereas it is well established that some X-linked genes "escape" X inactivation and are expressed from both active (Xa) and inactive (Xi) X chromosomes, most models for the chromosomal control ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.13.7364
更新日期:1999-06-22 00:00:00
abstract::Recent anatomical tracing studies have yielded substantial amounts of data on the areal connectivity underlying distributed processing in cortex, yet the fundamental principles that govern the large-scale organization of cortex remain unknown. Here we show that functional similarity between areas as defined by the pat...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1414153111
更新日期:2014-11-18 00:00:00
abstract::Polyadenylation, the process of eukaryotic mRNA 3' end formation, is essential for gene expression and cell viability. Polyadenylation of male germ cell mRNAs is unusual, exhibiting increased alternative polyadenylation, decreased AAUAAA polyadenylation signal use, and reduced downstream sequence element dependence. C...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0707589104
更新日期:2007-12-18 00:00:00
abstract::Heparin-binding growth factor type 1 (HBGF-1; sometimes termed acidic fibroblast growth factor) is potentially an important factor in liver regeneration. HBGF-1 alone (half-maximal effect at 60 pM) stimulated hepatocyte DNA synthesis and bound to a high-affinity receptor (Kd = 62 pM; 5000 per cell). Epidermal growth f...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.86.19.7432
更新日期:1989-10-01 00:00:00
abstract::Rhythmic, spontaneously pulsating cardiac cells cultured from newborn rats are immediately stimulated to beat faster by addition of a number of tubulin-binding agents but not by their non-tubulin-binding analogues. The tubulin-binding agents tested include vinblastine, vincristine, navelbine, two analogs of vinblastin...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.89.4.1256
更新日期:1992-02-15 00:00:00
abstract::Fish stocks experiencing high fishing mortality show a tendency to mature earlier and at a smaller size, which may have a genetic component and therefore long-lasting economic and biological effects. To date, the economic effects of such ecoevolutionary dynamics have not been empirically investigated. Using 70 y of da...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1212593110
更新日期:2013-07-23 00:00:00
abstract::The araCBAD regulatory region of Escherichia coli contains two divergently oriented promoters and three sites to which AraC, the regulatory protein of the operon, can bind. This paper presents the results of in vivo dimethyl sulfate "footprinting" experiments to monitor occupancy of the three AraC sites and measuremen...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.15.5444
更新日期:1988-08-01 00:00:00
abstract::At the onset of apoptosis, the peroxidation of cardiolipin at the inner mitochondrial membrane by cytochrome c requires an open coordination site on the heme. We report a 1.45-Å resolution structure of yeast iso-1-cytochrome c with the Met80 heme ligand swung out of the heme crevice and replaced by a water molecule. T...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1323828111
更新日期:2014-05-06 00:00:00
abstract::Absorbance changes of C-550 and cytochrome b(559), and fluorescence-yield changes were measured during irradiation of chloroplasts at -196 degrees . The photo-reduction of C-550 proceeded more rapidly than the photo-oxidation of cytochrome b(559), and the fluorescence-yield change had similar kinetics to the cytochrom...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.69.11.3420
更新日期:1972-11-01 00:00:00
abstract::Homozygous uniparental mouse embryos, produced by microsurgical removal of the male pronucleus from fertilized eggs and diploidization of the female pronucleus with cytochalasin, were surrounded with blastomeres from normal embryos to produce chimeric embryos. A few of these chimeras developed into viable adults, and ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.17.6509
更新日期:1986-09-01 00:00:00
abstract::We have compared the process of prophage lambda induction with that of prophage Mu. According to the Campbell model, rescue of lambda DNA from the host DNA involves reversal of lambda integration such that the prophage DNA is excised from the host chromosome. We have monitored this event by locating the prophage DNA w...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.74.8.3143
更新日期:1977-08-01 00:00:00
abstract::The second structure of a eukaryotic RNA polymerase II so far determined, that of the enzyme from the fission yeast Schizosaccharomyces pombe, is reported here. Comparison with the previous structure of the enzyme from the budding yeast Saccharomyces cerevisiae reveals differences in regions implicated in start site s...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0903361106
更新日期:2009-06-09 00:00:00
abstract::Misfolded proteins are eliminated from the endoplasmic reticulum (ER) by retrotranslocation into the cytosol, a pathway hijacked by certain viruses to destroy MHC class I heavy chains. The translocation of polypeptides across the ER membrane requires their polyubiquitination and subsequent extraction from the membrane...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0505006102
更新日期:2005-10-04 00:00:00
abstract::The pancreatic beta cell can respond in the long term to hyperglycemia both with an increased capacity for insulin production and, in susceptible individuals, with apoptosis. When glucose-induced apoptosis offsets the increasing beta cell capacity, type 2 diabetes results. Here, we tested the idea that the pathway of ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.97.6.2820
更新日期:2000-03-14 00:00:00
abstract::Human X chromosome DNA was partially purified from a mouse-human hybrid cell line containing a single human chromosome, the X. Enrichment of such DNA was accomplished by two sequential reassociations of radiolabeled hybrid cell DNA with large excesses of mouse DNA. Unreassociated hybrid cell DNA was used as a probe fo...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.76.12.6525
更新日期:1979-12-01 00:00:00
abstract::The chloroplast stromal proteins from spinach condense the two heterocyclic moieties of vitamin B1--4-methyl-5-(beta-hydroxyethyl)thiazole and 2-methyl-4-amino-5-hydroxymethylpyrimidine--in the presence of MgATP. We have taken advantage of this observation to study thiazole synthesis. We present data indicating that p...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.88.6.2042
更新日期:1991-03-15 00:00:00
abstract::A purified rabbit liver membrane protein that binds desialylated glycoproteins has been shown to be a mitogen for human peripheral lymphocytes. The mitogenic activity is specific for desialylated thymus-derived (T)-cells. The loss of mitogenicity upon exposure of the binding protein to neuraminidase and the inhibitory...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.74.2.676
更新日期:1977-02-01 00:00:00
abstract::Excitation of HbCO by a single 6-psec 530-nm pulse results in photodissociation with a first-order constant of 0.89 X 10(11) sec-1. The kinetics of photodissociation, monitored by following absorbance changes in the Soret band at 440 nm, are interpreted as corresponding to predissociation followed by a corssing into a...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.75.2.573
更新日期:1978-02-01 00:00:00
abstract::Insights into the pathogenesis of migraine with aura may be gained from a study of human Ca(V)2.1 channels containing mutations linked to familial hemiplegic migraine (FHM). Here, we extend the previous single-channel analysis to human Ca(V)2.1 channels containing mutation V1457L. This mutation increased the channel o...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.192242399
更新日期:2002-10-01 00:00:00
abstract::By using the maximum likelihood method, we made a genome-wide comparison of the evolutionary rates in the lineages leading to the laboratory strain (S288c) and a wild strain (YJM789) of Saccharomyces cerevisiae and found that genes in the laboratory strain tend to evolve faster than in the wild strain. The pattern of ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0409159102
更新日期:2005-01-25 00:00:00
abstract::Thrombin induces platelet aggregation and formation of a fibrin clot in platelet-rich plasma; leupeptin, a protease inhibitor, partially inhibits platelet aggregation, but it does not inhibit fibrin clot formation. Indomethacin does not inhibit either thrombin-induced platelet aggregation or fibrin clot formation. How...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.10.3456
更新日期:1986-05-01 00:00:00
abstract::Vasopressin's action in renal cells to regulate water transport depends on protein phosphorylation. Here we used mass spectrometry-based quantitative phosphoproteomics to identify signaling pathways involved in the short-term V2-receptor-mediated response in cultured collecting duct cells (mpkCCD) from mouse. Using St...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0910646107
更新日期:2010-02-23 00:00:00