Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. A superoxide dismutase [EC 1.15.1.1] was purified about 275-fold with a yield of 34% from Mycobacterium tuberculosis, strain H37Ra (attenuated strain), grown on a Sauton medium for two months. The purified enzyme was homogeneous as judged by polyacrylamide gel electrophoresis, and by analytical ultracentrifugation and sedimentation equilibrium studies. 2. The molecular weight of the enzyme was estimated to be approximately 88,000 by sedimentation equilibrium analysis. Since the molecular weight of the subunit was 21,000 as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis, the enzyme appears to be composed of four subunits of equal size. 3. Electron spin resonance (ESR) spectra showed that the enzyme contained ferric iron, and metal analysis showed that the enzyme contained ferric iron, and metal analysis showed that approximately 3.7 atoms of iron were present per mole of the enzyme, indicating the occurrence of 1 atom of iron per subunit. 4. The amino acid composition was apparently similar to those of the iron-containing superoxide dismutases from Escherichia coli, luminous bacteria, Pseudomonas ovalis, and blue-green alga. 5. Antibodies against the enzyme were raised in rabbits and immunological studies were performed. The enzyme from M. tuberculosis, strain H37Rv (virulent strain), was found to have antigenic structures identical with those of the H37Ra enzyme. On the other hand, the manganese-containing superoxide dismutases from other species of mycobacteria, i.e., Mycobacterium species, strain Takeo, M. phlei and M. lepraemurium, showed only partial immunological identity with the H37Ra enzyme. 6. During the growth of M. tuberculosis, strain H37Ra, the enzyme was found to be secreted into the culture medium.
 ...
PMID:Superoxide dismutase from Mycobacterium tuberculosis. 82 61

A radioimmunoassay was developed for murine lactoferrin (LF), a non-heme, iron-binding glycoprotein which appears to be a specific biochemical marker of differentiation in several cell types. Lactoferrin was labeled with 125I by the chloramine-T method to yield a product having 20 muCi/mug protein and an isotope incorporation of 0.6 atoms of 125I per molecule. Separation of bound and free lactoferrin was accomplished by either of two procedures, a double-antibody technique or precipitation in the presence of 50% saturated ammonium sulfate. The entire assay, including counting, was accomplished in less than 2 days and had a lower limit of sensitivity and a range of 1 ng/ml and 1-32 ng/ml, respectively, using rabbit antiserum in a dilution of about 1:10,000. The binding between LF and rabbit antiserum exhibited two association constants having values of 1.8 x 10(11) and 1 x 10(9) l/mole. The assay was specific for lactoferrin and no cross-reactivity was observed with transferrin, a similar non-heme, iron-binding glycoprotein. Human lactoferrin specifically reacted with anti-mouse lactoferrin, but the binding was approximately 8000 times weaker than observed with mouse lactoferrin. Values for lactoferrin in milk and bone marrow granulocytes were obtained which agreed with levels obtained using other methods.
 ...
PMID:Radioimmunoassay for murine lactoferrin, a protein marker of myeloid and mammary epithelial secretory cell differentiation. 83 25

The potent and specific inhibitor of anion permeability, 4,4'-diisothicyanostilbene-2,2'-disulfonic acid (DIDS) was synthesized in tritiated form ([3H]DIDS) from tritiated 5-nitrotoluene-o-sulfonic acid. Its reactions with and effects on red blood cells were compared with those of a reduced form ([3H]H2DIDS), previously used as a tracer for DIDS. The rate of covalent reaction of [3H]DIDS was substantially faster than that of [3H]H2DIDS at all temperatures tested. With both agents, the rate of reaction was increased in alkaline media, although the response occurred at a lower pH with [3H]DIDS. On the other hand, the relationship of irreversible membrane binding to the degree of inhibition of sulfate fluxes was linear and virtually the same for both agents, with 100% inhibition associated with the binding of approximately 1.2 X 10(6) molecules per cell. About 90% of the binding for each probe was to a particular membrane protein, known as band 3, equivalent to about 1 mole of agent per mole of protein.
 ...
PMID:Synthesis of tritiated 4,4'-diisothiocyano-2,2'-stilbene disulfonic acid ([3H]DIDS) and its covalent reaction with sites related to anion transport in human red blood cells. 86 93

alpha-Amylase was extracted from human pancreas and purified by using ammonium sulfate fractionation, Sephadex G-100 and DEAE-Sephadex A-50 column chromatography. The enzyme was shown to be homogenous by three different criteria: polyacrylamide disc gel electrophoresis, SDS polyacrylamide gel electrophoresis and analytical ultracentrifugation. The values of SO20,w, D20,w, v, and frictional ration of the enzyme were calculated to be 5.01S, 7.56D, 0.718 ml g-1 and 1.10, respectively. The molecular weight of the alpha-amylase was determined by three different methods: sedimentation velocity-diffusion, conventional sedimentation equilibrium and SDS polyacrylamide gel electrophoresis and was found to be 57,850; 50,100 and 53,200 g mole-1, respectively (average value 53,700). The amino acid composition of the enzyme was determined and compared with those of alpha-amylases from various other sources.
 ...
PMID:Human pancreatic alpha-amylase. I. Purification and characterization. 90 Aug 59

Light chains of skeletal muscle myosin were studied through the reactivity of their SH groups with a fluorescent thiol reagent, N-(7-dimethylamino-4-methylcoumarinyl) maleimide (DACM). The experiments were carried out by reacting the reagent with myosin for a short time and measuring the amounts of reacted dye by fluorometry after separating light chains by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The two classes of light chains, alkali light chains and DTNB light chain, were clearly distinguished by their manner of reactivity change, and differences in their environment and in their function were suggested. Although we found that the SH groups of the DTNB light chain were susceptible to very low concentrations of Mg ions (of the order of 10-5 M), we could not observe Ca2+-induced conformational change by our technique. We also estimated the stoichiometry of light chains in skeletal muscle myosin to be 1.37 mol alkali light chain 1, 1.95 mol of DTNB light chain and 0.77 mol of alkali light chain 2 per mole of myosin from the total amounts of our reagent that reacted with each light chain.
 ...
PMID:Fluorometric studies on the light chains of skeletal muscle myosin. I. Effects of temperature, ionic strength, divalent metal ions, and nucleotides. 91 9

Four major glycoproteins were extracted by dilute salt solution from procine mitral valvular tissue. Two of these major glycoproteins, procine valve glycoprotein I and porcine valve glycoprotein III, were isolated and purified by fractionation of salt extract with ammonium sulfate followed by column chromatography on DEAE-cellulose. The purified glycoproteins appeared to be homogeneous by polyacrylamide disc electrophoresis in several buffer systems, and by Sephadex filtration. The porcine valve glycoprotein I has a molecular weight of approximately 120000. Isoelectric focusing yielded a single band, pI = 5.8. The glycoprotein contained large amounts of acidic amino acids, and amide nitrogen. The carbohydrate moiety was composed of fucose, mannose, galactose, glucose, glucosamine, and galactosamine in the molar ratio of 5:10:15:12:7:2 per mole of glycoprotein. The second major glycoprotein, porcine valve glycoprotein III, has an approximate molecular weight of 72000. This glycoprotein gives two bands upon analytical isoelectric focusing with isoelectric points of pI = 4.1 and 4.3. Porcine valve glycoprotein III contained large amounts of acidic amino acids and low amounts of amide nitrogen. Its carbohydrate moiety was composed of glucose, galactose, mannose, fucose, glucosamine, and sialic acid in the ratio of 3:3:2:1:4:1 mol/mole of glycoprotein. This glycoprotein was similar to a glycoprotein preparation isolated from porcine aortic intima by P.V. Wagh and B.I. Roberts (1972), Biochemistry 11, 4222.
 ...
PMID:Purification and chemical characterization of salt-extractable glycoproteins from porcine mitral valve. 93 28

The digestion of EF-Tu-GDP (or EF-Tu-GTP) by trypsin [EC 3.4.21.4] under native conditions has been shown to proceed through two different and characteristic stages. 1. In the first phase, the protein is transformed into a fragment (Fragment A) with a molecular weight of 39,000 by exposure to trypsin for a relatively short period of time. Fragment A is unable to catalyze the binding of aminoacyl-tRNA to ribosomes. The ability to promote two partial steps of the binding reaction, i.e., formation of the aminoacyl-tRNA-EF-Tu-GTP ternary complex as well as the methanol-stimulated, ribosome dependent GTPase reaction, was rapidly destroyed. On the other hand, the ability to interact with guanine nucleotides as well as EF-Ts survived well during prolonged digestion. 2. In the second phase of digestion, a nick is introduced in Fragment A to yield two subfragments (Fragments B and C). These two fragments exist as a hybrid molecule which migrates as a single peak on a Sephadex G-75 column, and which dissociates into Fragments B and C only in the presence of 6 M guanidine hydrochloride or 5% sodium dodecyl sulfate. The molecular weights of Fragments B and C, as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, were 22,000 and 12,000 respectively. The hybrid molecule still retained one mole of bound guanine nucleotide and was resistant to further tryptic digestion. 3. Three sulfhydryl groups of EF-Tu were found to be present in Fragment B, both by amino acid analysis of the purified fragments and also by electrophoresis of tryptic digests labeled with N-ethyl[14C]maleimide. 4. The tryptic digestion of EF-Tu-GDP (or EF-Tu-GTP) labeled with N-(1-anilinonaphthyl-4)maleimide (ANM) at SH2 (the second SH), caused a 30% decrease in the fluorescence emission during the first rapid phase of digestion. This indicates that destruction of the hydrophobic environment near SH2 of EF-Tu occurred in the early phase of tryptic digestion. 5. The kinetic studies on the reaction of ANM with EF-Tu before and after tryptic digestion indicated that both Fragment A and the hybrid molecule reacted with ANM in the presence of GTP three to four times more rapidly than in the presence of GDP. Thus, it appears that the ability to induce conformational transition near SH2 by a change of nucleotide ligands is still retained in the hybrid molecule consisting of Fragments B and C.
 ...
PMID:Limited hydrolysis of the polypeptide chain elongation factor Tu by trypsin. Isolation and characterization of the polypeptide fragments. 93 63

Synthetic polypeptides consisting of copolymers of glutamic acid and leucine have been shown to be useful materials for the fabrication of practical, biodegradable delivery vehicles for narcotic antagonists. Model delivery vehicles in film form were prepared from copolymers containing 10 mole percent to 40 mole percent glutamic acid, and loaded with 10% to 40% naltrexone by weight. The naltrexone was found to be released by diffusion, exhibiting diffusion coefficients that varied as a function of the glutamic acid content and the initial naltrexone loading. A wide range in diffusion coefficients were achieved (0.31 x 10-7 cm2/hr to 120 x 10-7 cm2/hr), leading to release rates within practical ranges of interest for meeting the program goals. We have demonstrated that the polypeptides can be fabricated into dosage forms that are amenable to administration by trochar. For example, rods 0.4 mm to 0.8 mm in diameter containing as much as 40% naltrexone by weight were extruded using a simple compression mold and die arrangement. An in vitro evaluation of the rods showed that antagonist is released by diffusion at a continuously decreasing rate, a behavior similar to that observed with the film devices that were, nonetheless, capable of blocking an AD80 challenge of morphene sulfate in mice for more than 30 days. One of the most promising delivery vehicles that we have developed to date consists of a polypeptide tube filled with a naltrexone/polypeptide core. Preliminary experiments have shown that these devices may be capable of administering high, constant rates of release for prolonged periods of time. Additional work, however, is required to develop techniques for the preparation of reproducible delivery vehicles.
 ...
PMID:Use of synthetic polypeptides in the preparation of biodegradable delivery vehicles for narcotic antagonists. 96 33

The presence of a single cysteine in the sweet-tasting protein monellin was confirmed by titrations with p-hydroxymercuribenzoate (PHMB) and 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB). The sulfhydryl group in native monellin reacts very slowly with each of these reagents, indicating that the sulfhydryl is relatively inaccessible. In the presence of either 6 M guanidine-HCl, 8 M urea, or 1% sodium dodecyl sulfate, the rate of reaction of the sulfhydryl group with titrant is dramatically increased. Under a variety of conditions, the presence of 1 mole of sulfhydryl per mole of protein (of molecular weight 10,700) was found. Reaction of the sulfhydryl by titration with PHMB or DTNB leads to loss of sweetness. The free sulfhydryl is also lost by carboxymethylation of monellin in the presence of guanidine-HCl, yielding a protein that is not sweet. Exposure to air in the presence of denaturant leads to a decrease in the sweetness of monellin. Sweetness of the PHMB-reacted monellin can be recovered upon treatment of the protein with mercaptoethanol, and the partial loss of sweetness that occurs with air exposure is lessened in the presence of mercaptoethanol. It is postulated that alteration of the single sulfhydryl group of monellin leads to a change in the tertiary structure of the protein and hence its sweet taste.
 ...
PMID:The sulfhydryl group of monellin: its chemical reactivity and importance to the sweet taste. 96 95

DIDS (4,4'-diisothiocyano stilbene-2,2'-disulfonic acid) and H2DIDS (4,4'-diisothiocyano-1,2-diphenyl ethane-2,2'-disulfonic acid) binding to the human red cell membrane proteins were studied as a function of concentration, temperature and time. Most binding sites were common to both. The common sites were in band 3 of SDS polyacrylamide gel electropherograms (Steck, 1974. J. Cell Biol. 62:1), an unidentified adjacent band, and glycophorin. Reversible and irreversible binding occurred; both inhibited sulfate equilibrium exchange. The time courses of irreversible binding to band 3 and total binding to the membrane as a whole were biphasic. About 20% of H2DIDS and greater 60% of DIDS binding were rapid, independent of temperature. Slow H2-DIDS binding was monoexponential, activation enthalpy 23 kcal/mole. The stoichiometry of irreversible H2DIDS binding to band 3 was 1.1-1.2, concentration-dependent. Under the conditions studied (0-50 muM, hematocrit 10%, 5-37 degrees C) binding to band 3 was a constant fraction of total binding, 0.7 for H2DIDS and 0.8 for DIDS. Inhibition was a linear function of total binding, binding to band 3, and therefore also to nonband 3 sites, with either inhibitor during both phases, H2DIDS inhibition was complete at 1.9 X 10(6) or 1.2 X 10(6) molecules/cell total and band 3 binding respectively. For DIDS the corresponding figures were 1.3 X 10(6) and 1.1 X 10(6). It is shown how reagents of mixed function can react with biphasic kinetics. Binding to multiple contiguous sites may exhibit concentration-dependent stoichiometry. Under such conditions a linear inhibition-binding relationship is neither a necessary nor a sufficient condition for the identification of transport sites.
 ...
PMID:A study of the relationship between inhibition of anion exchange and binding to the red blood cell membrane of 4,4'-diisothiocyano stilbene-2,2'-disulfonic acid (DIDS) and its dihydro derivative (H2DIDS). 97 16


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>