Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The sarcoplasmic Ca(2+)-ATPase was reduced with 300 mM 2-mercaptoethanol at elevated temperatures (40-45 degrees C) with a concomitant loss of ATPase activity. The reduction and inactivation of the Ca(2+)-ATPase proceeded rapidly in the absence of Ca2+. The Ca(2+)-ATPase was also inactivated with 2-mercaptoethanol in the presence of diluted SDS (0.4 mg/ml) even at 20 degrees C. In contrast to the (Na+, K+) ATPase, the inactivated Ca(2+)-ATPase in the presence of diluted SDS was sedimented by the centrifugation at 100,000 x g for 30 min.
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PMID:Reduction and inactivation of the sarcoplasmic Ca(2+)-ATPase by 2-mercaptoethanol--contrast to the (Na+,K+) ATPase. 133 62

Many neurohormones alter the force of cardiac contraction by variations in the intracellular Ca2+ concentration. alpha 1-Adrenergic and muscarinic stimulations, rather, modify the sensitivity of contractile proteins to Ca(2+)-calmodulin-myosin light-chain kinase (MLCK) complex induces a large increase in Ca2+ sensitivity (0.14 pCa unit) of these easily accessible myofilaments. This increase is further enhanced by up to 0.19 pCa unit when protein kinase C (PKC) is added together with MLCK. Similarly, the Ca2+ ATPase activity of skinned cells in suspension is increased in the presence of MLCK and further in the presence of both kinases. 32P-labelling and SDS/PAGE show that these changes are associated with light-chain 2 (LC2) phosphorylation together with phosphorylation of troponin I and troponin T when PKC is added. Although to a smaller extent than in smooth muscle, phosphorylation of cardiac myosin LC2 may be involved in the modulation of heart contractility.
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PMID:Protein kinase C enhances myosin light-chain kinase effects on force development and ATPase activity in rat single skinned cardiac cells. 138 18

The expression of troponin T, a thin filament regulatory protein, was examined in normal and failing left ventricles. The samples were obtained from the hearts of patients with severe heart failure who were undergoing cardiac transplantation, and from normal adult hearts that could not be used for transplantation. Western blots of the myofibrillar proteins demonstrated two isoforms, troponin T 1 (TnT1) and troponin T 2 (TnT2). TnT2 is expressed at significantly higher levels in failing hearts (p less than 0.004). Western blots of two-dimension SDS-PAGE gels resolved two dominant spots of TnT1 and of TnT2 and several minor troponin T species. Alkaline phosphatase treatment markedly decreased the sizes of the two acidic spots while increasing the two more basic spots by a comparable amount. Myofibrillar ATPase activity had an inverse and negative linear relationship (r = 0.7, p less than 0.02) with the myofibrillar percentage of total troponin T comprised of TnT2. In that heart failure in these transplant patients had multiple bases, we propose that rather than a cause of heart failure, the disease-associated changes in troponin T isoform expression are an adaptation to abnormal myocardial function.
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PMID:Troponin T isoform expression in the normal and failing human left ventricle: a correlation with myofibrillar ATPase activity. 138 29

Fluorescein 5'-isothiocyanate (FITC) was used to modify the lysine residue in the active site of tonoplast H(+)-ATPase from etiolated mung-bean (Vigna radiata L.) seedlings. FITC caused marked inactivation of the enzyme activities of both membrane-bound and soluble ATPase and its associated H+ translocation. The SDS/PAGE pattern revealed that the FITC-binding site was in the large (A) subunit of ATPase. Inhibition could be substantially prevented by its physiological substrate ATP, pyrophosphate and nucleotides in the decreasing order: ATP greater than pyrophosphate greater than ADP greater than AMP greater than GTP greater than CTP greater than UTP. The mode of inhibition by FITC was competitive with respect to ATP. Loss of ATPase activity followed pseudo-first-order kinetics with a Ki of 0.33 mM, a minimum inactivation half-time of 110 s, and a first-order rate constant of 0.244 s-1. A double-logarithmic plot of apparent rate constant versus FITC concentration gave a slope of 0.913, indicating that inactivation results from reaction of at least one lysine residue at the catalytic site of the large subunit. Labelling studies indicated that the incorporation of approx. 1 mol of FITC/mol of ATPase is sufficient to inhibit ATPase completely. The enhancement and blue shift of emission maxima of FITC after modification of ATPase indicated that the labelled lysine residue was located in a relatively hydrophobic domain.
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PMID:Inhibition of tonoplast ATPase from etiolated mung bean seedlings by fluorescein 5'-isothiocyanate. 138 33

We have analyzed extragenic suppressors of paralyzed flagella mutations in Chlamydomonas reinhardtii in an effort to identify new dynein mutations. A temperature-sensitive allele of the PF16 locus was mutagenized and then screened for revertants that could swim at the restrictive temperature (Dutcher et al. 1984. J. Cell Biol. 98:229-236). In backcrosses of one of the revertant strains to wild-type, we recovered both the original pf16 mutation and a second, unlinked suppressor mutation with its own flagellar phenotype. This mutation has been identified by both recombination and complementation tests as a new allele of the previously uncharacterized PF9 locus on linkage group XII/XIII. SDS-PAGE analysis of isolated flagellar axonemes and dynein extracts has demonstrated that the pf9 strains are missing four polypeptides that form the I1 inner arm dynein subunit. The primary effect of the loss of the I1 subunit is a decrease in the forward swimming velocity due to a change in the flagellar waveform. Both the flagellar beat frequency and the axonemal ATPase activity are nearly wild-type. Examination of axonemes by thin section electron microscopy and image averaging methods reveals that a specific domain of the inner arm complex is missing in the pf9 mutant strains (see accompanying paper by Mastronarde et al.). When combined with other flagellar defects, the loss of the I1 subunit has synergistic effects on both flagellar assembly and flagellar motility. These synthetic phenotypes provide a screen for new suppressor mutations in other loci. Using this approach, we have identified the first interactive suppressors of a dynein arm mutation and an unusual bypass suppressor mutation.
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PMID:Extragenic suppressors of paralyzed flagellar mutations in Chlamydomonas reinhardtii identify loci that alter the inner dynein arms. 138 4

The aim of the present work was to compare the structure and protein composition of centrioles from spermatozoa of sturgeon and salmon fishes. The total protein content of the extracted fractions was studied by Na-SDS electrophoresis. Proteins with molecular weights from 15 to 170 kDa were detected. In both cases the major protein of centrioles is a protein with a molecular weight equal to that of tubulin. A protein with the molecular weight corresponding to actin was also detected. In both cases the ATPase activity stimulated by Ca2+ and Mg2+ ions was revealed. Electron microscopic studies showed differences in the ultrastructure of centrioles from sturgeon and salmon spermatozoa.
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PMID:[Comparative study of the structure and protein composition of spermatozoid centrioles from sturgeons and salmon]. 138 8

Calcium-dependent regulation of tension and ATPase activity in permeabilized porcine ventricular muscle was lost after incubation with 10 mM vanadate. After transfer from vanadate to a vanadate-free, low-Ca2+ solution (pCa greater than 8), the permeabilized muscle produced 84.8% +/- 20.1% (+/- S.D., n = 98) of the isometric force elicited by high Ca2+ (pCa approximately 4.5) prior to incubation with vanadate. Transfer back to a high Ca2+ solution elicited no additional force (83.2% +/- 18.7% of control force). SDS-PAGE and immunoblot analysis of fibers and solutions demonstrated substantial extraction (greater than 90%) of Troponin I (TnI). Calcium dependence was restored after incubation with solutions containing either whole cardiac troponin or a combination of TnI and troponin C subunits. This reversible extraction of troponin directly demonstrates the role of TnI in the regulation of striated muscle contractility and permits specific substitution of the native TnI with exogenously supplied protein.
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PMID:Troponin replacement in permeabilized cardiac muscle. Reversible extraction of troponin I by incubation with vanadate. 139 78

1. The present study demonstrated that the Ca(2+)-ATPase activity of the plasma membrane-rich fraction from bovine parotid gland was decreased by the addition of reducing agents. 2. Ca(2+)-ATPase activity staining on SDS-PAGE gels was lost in the presence of 2-mercaptoethanol. 3. Among all the reducing agents tested, GSH was the most effective in inhibiting Ca(2+)-ATPase. 4. The Ca(2+)-ATPase activity decreased by the GSH was restored by the addition of an oxidizing reagent. However, oxidation with an oxidizing reagent subsequent to alkylation of the reduced enzyme with iodoacetamide resulted in no restoration of activity. 5. The decrease of Ca(2+)-ATPase activity by GSH is due to a decrease in the Vmax of the enzyme. 6. These results suggest that the disulfide bond in this enzyme protein is necessary to maintain the activity of this enzyme.
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PMID:Inhibitory effect of sulfhydryl group on Ca(2+)-ATPase activity in the plasma membrane-rich fraction from bovine parotid gland. 142 64

Nascent synthesis and accumulation of germin and its mRNA mark the onset of renewed growth when wheat embryos are germinated in water. Germin is a water-soluble, pepsin-resistant protein that is not found in immature embryos, or in mature embryos before their germination. An antiserum was raised by injecting rabbits with germin that was freed of other proteins by pepsinization and gel filtration. The antiserum has been used to detect, in extracts of mature embryos from dry, ungerminated wheat grains, a protein that is antigenically related to germin. The antigenically related protein has been named pseudogermin. Pseudogermin accumulates, maximally, between 20-25-days postanthesis, then declines appreciably in amount by 30-days postanthesis, in soluble extracts of immature embryos from several wheat varieties. The antiserum was also used to identify germin and pseudogermin among the proteins extracted from cell walls and to bind immunogold to cell walls preparatory to visualizing freeze-cleaved embryos by scanning electron microscopy. Wall-associated germin accounts for about 40% of the total germin in germinating wheat embryos. Appearance of germin in the apoplast is the most conspicuous germination-related change in the distribution of cell-wall proteins. It seems that germin may act at the level of the apoplast and that pseudogermin may subsume the role of germin at low water potentials during embryogenesis. The N-terminal eicosapeptide sequences in germin and pseudogermin are very similar but SDS/PAGE analysis detects discrete differences between the mobilities of their constituent monomers as well as gross differences between the stabilities of the parent oligomers. Like germin, pseudogermin is a water-soluble, pepsin-resistant protein, but pseudogermin has unprecedented disulphide-independent thermostability properties that have never been previously reported for a water-soluble oligomeric protein. Polysaccharides that co-purify with otherwise pure specimens of germin (and pseudogermin) have been isolated for analysis and shown to be highly substituted glucuronogalactoarabinoxylans. The possible biological significance of selective and tenacious association between germin and glucuronogalactoarabinoxylans is discussed in relation to cell expansion during embryogenic and germinative development of wheat, as are some peculiarities of amino-acid sequence that suggest a possible relation between germin and a proton-specific ion pump: gastric ATPase.
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PMID:Germin isoforms are discrete temporal markers of wheat development. Pseudogermin is a uniquely thermostable water-soluble oligomeric protein in ungerminated embryos and like germin in germinated embryos, it is incorporated into cell walls. 142 3

Ubiquitinated proteins are degraded by a 26 S ATP-dependent protease. SDS-polyacrylamide gel electrophoresis analysis of the purified 26 S enzyme reveals more than 20 polypeptides ranging in apparent molecular masses from 20 to 110 kDa. Although many of the subunits smaller than 30 kDa are members of the multicatalytic protease family, the identity and function of the larger polypeptides have remained unknown. We report here the cDNA sequence for subunit 4, a 51-kDa chain of the 26 S protease. Subunit 4 belongs to a recently identified eukaryotic ATPase family, which includes proteins involved in peroxisome formation, secretion, and human immunodeficiency virus gene expression. Subunit 4 also shows weak similarity to ClpA, the ATP-binding subunit of the Escherichia coli protease, Clp.
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PMID:Subunit 4 of the 26 S protease is a member of a novel eukaryotic ATPase family. 142 20


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