SEARCH · PubMed Health

Results for “Dimethyl Suberimidate”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources

PubMed1979

Cross-linking experiments with the adenosine triphosphatase of sarcoplasmic reticulum.

The proteins of sarcoplasmic reticulum were cross-linked by rapid oxidation of thiol groups with I2. About two-thirds of the thiols were oxidized without any significant cross-linking, implying an extensive formation of intramolecular disulphide bonds. When the thiols were completely oxidized at room temperature a series of oligomers containing up to five molecules were observed, as well as large aggregates which were excluded from the gels. Complete oxidation at -10 degrees C left most of the ATPase (adenosine triphosphatase) as monomer. Similar results were obtained when copper-phenanthroline complexes or dimethyl suberimidate were used as cross-linking reagents. We conclude that most of the cross-linked species arise by linking of randomly colliding ATPase molecules which are present in the membrane at very high concentration.

Adenosine Triphosphatases↗

PubMed1984

Purification, crystallization, and molecular properties of aspartase from Pseudomonas fluorescens.

Aspartase [L-aspartate ammonia-lyase, EC 4.3.1.1] of Pseudomonas fluorescens was highly purified to homogeneity and crystallized. The purified enzyme sedimented as a monodisperse entity upon ultracentrifugation with a s0(20),w value of 8.6S. Upon polyacrylamide gel electrophoresis (PAGE), the enzyme migrated as a single band. The molecular weight of the native enzyme was 173,000 +/- 3,000, as determined by sedimentation equilibrium analysis, and that of the enzyme subunit was determined to be 50,000 +/- 1,500 by sodium dodecyl sulfate (SDS)-PAGE. Cross-linking experiments using dimethyl suberimidate followed by SDS-PAGE indicated that the native enzyme was composed of four subunits with identical molecular weight. The amino acid composition of the enzyme was determined.

Amino Acids↗

PubMed1985

Pseudocatalase from Lactobacillus plantarum: evidence for a homopentameric structure containing two atoms of manganese per subunit.

An improved procedure for the isolation of the pseudocatalase of Lactobacillus plantarum has been devised, and the quaternary structure and manganese content of this enzyme have been reexamined. Sedimentation equilibrium of the native enzyme at several salt concentrations gave a molecular weight of 172 000. The subunit weight, obtained by sedimentation equilibrium in 6.4 M guanidinium chloride, with or without prior reduction and carboxymethylation, was 34 kilodaltons. The amino acid composition indicated 150 Arg + Lys, and after exhaustive tryptic digestion, 32 peptides were resolved. These data suggest that the pseudocatalase is a homopentamer. Cross-linking with dimethyl suberimidate, followed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, yielded five major bands, another indication of pentameric structure. The manganese content was found to be 1.8-2.4 per subunit. S20,W was found to be 9.6 S and f/f0 = 1.2, suggesting a globular structure of Stokes radius 44 A.

Amino Acids↗

PubMed1983

Structural studies on the microfibrillar proteins of wool. Interaction between alpha-helical segments and reassembly of a four-chain structure.

The alpha-helix-rich particle of Mr 50 200, derived by limited alpha-chymotryptic digestion of the solubilized microfibrillar proteins from wool alpha-keratin, consists mainly of polypeptide-chain segments of Mr 12 500 (fraction ChC) and 25 000 (fraction ChB). The 12 500-Mr segments are of two types (I and II), which are derived from different polypeptide chains of the microfibrillar complex. Each of these type-I and type-II segments partially self-associates in benign solvents to form either dimers or tetramers. When mixed, the two segments show changes in physical properties (alpha-helix content, difference spectra and molecular weight) indicative of complex-formation. The maximum changes occur when the two segments are mixed in an equimolar ratio. Complexes isolated after rapid dialysis of mixtures from 8 M-urea solution were examined by various methods. A tetrameric structure is the main product formed in all cases, and the maximum amount of tetramer is obtained from equimolar mixtures of the type-I and type-II polypeptides. When urea is removed by dialysis from the unfractionated 12 500-Mr segments (fraction ChC) or from the alpha-helix-rich particle itself, a similar complex of Mr 50 000 is formed. The physical properties of these reconstituted entities (alpha-helix content, molecular weight, thermal stability and exposure of tyrosine residues) are similar to those of the original alpha-helix-rich particle. Cross-linking experiments with dimethyl suberimidate are in agreement with a four-chain complex for the reassembled structures. A pair of double-stranded alpha-helices is proposed for the particle, and is considered to be an integral part of the microfibrillar complex in wool alpha-keratin.

Animals↗

PubMed1992

Augmentation of alpha-actinin-induced gelation of actin by talin.

Interactions among the three major constituents of focal adhesions, talin, actin, and alpha-actinin, were studied. No evidence was obtained for the direct interaction between talin and alpha-actinin. Both talin and alpha-actinin increased the rate and extent of polymerization of actin, and their effects were additive. Whereas talin alone exhibited very little actin-gelating activity, it potentiated markedly the gelation in the presence of alpha-actinin and lowered the concentration of alpha-actinin necessary for the gel formation. Its gelation-potentiating activity on prepolymerized actin was much smaller than observed on G-actin. Treatment of talin with a cross-linking reagent, 1-ethyl-3[3-(dimethylamino)propyl]carbodiimide or dimethyl suberimidate, resulted in the formation of its oligomeric polypeptides. The complexes of talin and G-actin were also demonstrated with the cross-linking reagents and fluorescence-labeled actin. These results indicate that talin is able to cross-link some limited regions of actin filaments.

Actinin↗

PubMed1986

Isolation and characterization of a high molecular weight stable pink form of uteroferrin from uterine secretions and allantoic fluid of pigs.

A pink, high molecular weight form of uteroferrin (Uf) has been isolated from uterine secretions and allantoic fluid of pigs. This protein fraction (denoted FIII) which is relatively stable under physiological conditions of pH, ionic strength, and temperature has a molecular weight of about 80,000, a value approximately twice that of purple Uf (Mr approximately 35,000) isolated from a separate fraction (FIV) by gel filtration. The visible absorption spectrum, EPR signal, and acid phosphatase activity of Uf in FIII are almost identical to those of FIV Uf after the latter has been reduced by 2-mercaptoethanol. However, unlike reduced FIV Uf, the pink, high molecular form does not revert to purple, nor does it show loss of EPR signal and phosphatase activity in the presence of oxygen. In addition, it does not become purple at orthophosphate concentrations which inhibit Uf acid phosphatase activity. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate has shown that FIII consists of approximately equal amounts of Uf polypeptides (Mr = 35,000 and 37,000) and a group of three polypeptides (Mr = 40,000, 46,000, and 50,000) antigenically unrelated to Uf. The latter share a common epitope not found on Uf and are probably differentially processed forms of the same protein. FIII can be dissociated by pH conditions below 5.0, by exposure to antibodies raised against Uf or the associated polypeptides, and by sodium dodecyl sulfate at 100 degrees C. The polypeptides in FIII are not therefore linked by disulfide bonds. Treatment with dimethyl suberimidate, however, results in a cross-linked complex (Mr approximately 82,000) consisting of Uf and the associated polypeptides. It is concluded that this high Mr form of Uf is a heterodimer of fully activated Uf and a second polypeptide of unknown function.

Acid Phosphatase↗

PubMed1988

Tetrameric structure of the nonactivated glucocorticoid receptor in cell extracts and intact cells.

Mouse lymphoma cells contain a nonactivated glucocorticoid receptor of Mr approximately 330,000 which is heteromeric in nature and is unable to bind to DNA. Following affinity labeling of the steroid-binding subunit and subsequent cross-linking with dimethyl suberimidate at various times either in cell extracts or in intact cells, a series of labeled bands was detected in SDS gels. From the molecular masses of completely and partially cross-linked complexes we conclude that the large nonactivated receptor is a tetramer composed of two 90 kDa subunits, one 50 kDa polypeptide and one steroid-binding subunit.

Animals↗

PubMed1975

[Nearest-neighbor relationships among 50S ribosomal proteins of E. coli].

Dimethyl suberimidate has been used to study the proximity relations between E. coli 50 S ribosomal proteins. The composition of two cross-linked protein complexes has been determined; one is a quaternary complex containg proteins L2, L20, L27 and L32-33, and the other is a ternary complex containing proteins L2, L13 and L20. The vicinity of these proteins in the ribosome is discussed.

Dimethyl Suberimidate↗

PubMed2002

Evidence for a dimeric structure of rat liver serine dehydratase.

Rat liver serine dehydratase (SDH) is known to be involved in gluconeogenesis. It has long been believed to be a dimeric protein with the subunit molecular weight (M(r)) of 34,000. Recently, sheep liver SDH was reported to be a monomer with a M(r) of 38,000. The native M(r) of rat SDH was only determined by the ultracentrifugation method more than three decades ago, and that of sheep SDH was done by the method of gel chromatography. The primary to quaternary structures of a given enzyme in a specific mammalian organ are usually conserved among various species. The aim of the present investigation is to clarify the structural differences between rat and sheep SDHs. First, we found that the amino acid composition reported for sheep SDH was statistically similar to that of rat SDH. Second, immunoblot analysis using anti-rat SDH IgG as the probe showed the size of sheep SDH to be a M(r) of 30,500, whereas that of SDH was about M(r) of 35,000. On the other hand, the native size of rat SDH was assessed by two methods: (1) the laser light scattering method demonstrated that rat SDH had a M(r) of 66,800, consistent with the previous value (M(r)=64,000); (2) cross-linking experiments of the purified rat SDH with dimethyl suberimidate revealed the existence of a dimeric form by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The present results clearly confirm that rat SDH is a dimer, and suggest that sheep SDH is similar to rat SDH immunologically, but with a molecular weight 7500 smaller than reported previously.

Amino Acids↗

PubMed1993

Interactive intermediates are formed during the urea unfolding of rhodanese.

Structural transitions have been studied on the pathway for urea denaturation of rhodanese. Unlike guanidinium hydrochloride, urea gives no visible precipitation. Increasing urea concentrations cause a transition in which the enzyme activity is completely lost by 4.5 M urea, and there is a shift of the intrinsic fluorescence maximum from 335 nm for the native enzyme to 350 nm. There is a maximum exposure of organized hydrophobic surfaces at 4.5 M urea as reported by the fluorescence of 1,1'-bi(4-anilino)naphthalene-5,5'-disulfonic acid. Above 4.5 M urea, this probe reports the progressive loss of organized hydrophobic surfaces. The polarization of the intrinsic fluorescence falls with increasing urea concentrations in a complex transition showing that rhodanese flexibility increases in at least two phases. Rhodanese becomes increasingly susceptible to digestion by subtilisin between 3.5 and 4.5 M urea, giving rise to large fragments. At urea concentrations > 5 M, rhodanese is completely digested. There is a small increase in the rate of sulfhydryl accessibility between 3.5 and 4.5 M urea, but there is a large increase in the sulfhydryl accessibility above 4.5 M urea. Dimethyl suberimidate cross-linking shows the presence of associated species in 3-5 M urea, but there are few cross-linkable species at lower or higher urea concentrations. These results are consistent with a model in which urea unfolding of rhodanese is associated with the initial production of a species having organized regions of structure with exposed hydrophobic surfaces separated by flexible elements.

Animals↗

PubMed1992

Properties of hypotonized, crosslinked and crosslinked- permeabilized rat erythrocytes as potential carrier systems.

The osmotic fragility curves of isotonic rat RBCs, studied at pH 8 to avoid the Hb insolubility, are similar to those in humans at pH 7.4. Hypotonized rat RBCs, either directly or dialysed (0-24 h), are more hemolysis-resistant than isotonic rat RBCs. The discocyte-stomatocyte-spherocyte transformation can be observed with scanning electron microscopy. Protein crosslinking with dimethyl suberimidate can stabilize RBCs. The crosslinking level (60%), the cellular yield (80%), the mechanical and hemolytic resistance and the protective effect of enzyme activities, were studied in crosslinked or crosslinked- permeabilized RBCs after digitonin treatment. The normal discocytic shape of RBCs under scanning electron microscopy becomes stomatocytic in crosslinked and crosslinked- permeabilized RBCs with an erosioned surface.

Animals↗

PubMed1977

The subunit structure of the arom multienzyme complex of Neurospora crassa. A possible pentafunctional polypeptide chain.

A new procedure for the purification of the arom multienzyme complex from Neurospora crassa is presented. Important factors are the inactivation of proteinases by phenylmethanesulphonyl fluoride and the use of cellulose phosphate as an affinity adsorbent. A homogeneous enzyme, with a specific shikimate dehydrogenase activity of 70 units/mg of protein, is obtained in 25% yield. Polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate, combined with cross-linking studies using dimethyl suberimidate, suggest that the complex is composed of two subunits of molecular weight 165000. Glycerol-density-gradient centrifugation indicates a molecular weight for the intact complex of about 270000. Evidence for the effects of proteolysis, both during the preparation and on storage of the purified complex, is presented, and previous reports in the literature of the occurrence of multiple subunits are discussed in this light.

Alcohol Oxidoreductases↗

PubMed1980

A nonamer of histones in chromatin.

The results of dimethyl suberimidate cross-linking experiments demonstrate that histone H1 can be cross-linked quantitatively to the histone octamer of mononucleosomes to yield a histone nonamer. By combining our cross-linking procedure with two-dimensional electrophoretic techniques, we show further that it is possible to trace the nucleosomal origins of a spectrum of cross-linked chromatin products.

Animals↗

PubMed1976

Use of cross-linking in studying the structure of RNA tumour viruses.

Treatment of intact avian myeloblastosis virus (AMV) with dimethyl suberimidate dihydrochloride (DMS), a cross-linking agent specific for amino groups, was found to result in progressive cross-linking among viral proteins, as revealed by polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecyl sulphate (SDS). Free viral proteins were not cross-linked. The cross-linked protein complex with an apparent molecular weight of 50,000 daltons was studied in detail.

Avian Leukosis Virus↗

PubMed1979

Cross-linking of iodine-125-labeled, calcium-dependent regulatory protein to the Ca2+-sensitive phosphodiesterase purified from bovine heart.

The calcium-dependent regulatory protein (CDR).Ca2+ sensitive cyclic nucleotide phosphodiesterase was purified to apparent homogeneity from bovine heart by using ammonium sulfate fractionation, DEAE-ceelulose chromatography, and CDR-Sepharose affinity chromatography. The enzyme was purifed 13 750-fold with a 10% yield and a specific activity of 275 mumol of cAMP min-1 mg-1. The purified enzyme ran as a single band during sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular weight of 57 000. Phosphodiesterase activity was stimulated 10-fold by Ca2+ and CDR with half-maximal activation occurring at 9 ng/assay. [125I]CDR was cross-linked to the purified phosphodiesterase by using dimethyl suberimidate Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the cross-linked products revealed a number of discrete 125I-labeled bands. The molecular weights of the cross-linked products indicate that the stoichiometry of the phosphodiesterase complex is A2C2, where A is the phosphodiesterase catalytic subunit and C is the calcium-dependent regulatory protein.

Animals↗

PubMed1975

An octamer of histones in chromatin and free in solution.

Crosslinking with dimethyl suberimidate reveals a chain of histone octamers in chromatin. The octamer can be isolated free in solution at high ionic strength and pH. The identification of dimers formed by crosslinking reveals two or more contacts of each histone with others within the octamer. The molecular weight (110,000) and pattern of dissociation of the octamer are compatible with the composition (F2A1)2(F3)2(F2A2)2(F2B)2.

Animals↗

PubMed1997

Cross-linked trimers of bovine ribonuclease A: activity on double-stranded RNA and antitumor action.

Trimers of bovine pancreatic RNase A were obtained by cross-linking native RNase A with dimethyl suberimidate. They degrade double-stranded RNA more efficiently than dimers and monomers of RNase A, and display significant cytotoxic and/or cytostatic actions against C4-I cells (a human cell line derived from squamous carcinoma of the uterus cervix). On the same cell line cross-linked dimers of RNase A appear to be ineffective.

Animals↗

PubMedDate not supplied

[Polydispersity of Serratia marcescens nuclease at optimal pH values].

Treatment with dimethyl suberimidate, a cross-linking bifunctional agent, showed that Sm1 and Sm2 nucleases of Serratia marcescens B10M1 are polydisperse in solution and consist of monomers and dimers at the level of pH optimal for the enzyme activity. The data suggest that nucleases from the strain B10M1 and any other strain are polydisperse at pH optimum if their amino acid sequences are identical.

Amino Acid Sequence↗