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

1. Pyridoxal 5'-phosphate inhibits glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides reversibly which Ki equals 0.04-0.06 mM. 2. This inhibition is competitive with respect to glucose 6-phosphate and non-competitive with respect to NADP+ or NAD+. Interaction between enzyme and excess pyridoxal 5'-phosphate follows pseudo-first-order kinetics and indicates that one molecule of inhibitor reacts with each active unit of enzyme. 3. Substrate and coenzyme protect the enzyme from inhibition by pyridoxal 5'-phosphate. Dissociation constants for NADP+ and glucose 6-phosphate were determined from their effects on the kinetics of enzyme--inhibitor interaction. 4. Reaction of the enzyme with pyridoxal 5'-phosphate produces a typical Schiff-base absorbance peak at 430 nm. Subsequent reduction with sodium borohydride leads to spectral changes characteristic for the formation of a secondary amine. 5. The irreversibly inactivated enzyme thus produced contains two moles of inhibitor per mole of enzyme (two subunits per mole). After protein hydrolysis, N-6-pyridoxyllysine can be identified by paper chromatography. 6. The enzyme is inhibited irreversibly by 1-fluoro-2,4-dinitrobenzene, even in the presence of excess 2-mercaptoethanol. At least one dinitrophenyl group is bound per active unit of enzyme; 4 to 5 moles of dinitrophenyl group are bound per mole of enzyme. NADP+ AND GLUCOSE 6-PHOSPHATE PROTECT AGAINST INHIBITION BY 1-FLUORO-2,4-DINITROBENZENE. The absorption spectrum of dinitrophenyl-enzyme corresponds to that for dinitrophenylated amino groups. 7. These studies indicate that there is an essential lysine at the active site of the enzyme. It is suggested that the function of this lysine is to bind glucose 6-phosphate. 8. It is proposed that a group of "active lysine" proteins may exist (in analogy with the "active serine" enzymes), which share a common structural feature at their substrate-binding site and to which pyridoxal 5'-phosphate binds specifically.
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PMID:Evidence for an essential lysine in glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides. 23 86

A dihydrodipicolinate reductase containing flavin was purified from sporulating Bacillus subtilis PCI 219. The purified enzyme appeared homogeneous by dise gel electrophoresis. Its molecular weight was estimated as 74,000 by gel filtration on Sephadex G-200, and as 18,500 by electrophoresis on sodium dodecylsulfate polyacrylamid gel. These results suggest that the enzyme is composed of four subunits. The prosthetic group was identified as FMN, and one mole of the enzyme contained two moles of FMN. Both NADPH and NADH acted as coenzyme, though NADH was less effective. The enzyme also exhibited diaphorase activity. The pH optimum was 6.1. The enzyme was inhibited by dipicolinate but not by lysine or alpha, epsilon-diaminopimelate.
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PMID:A new flavin enzyme catalyzing the reduction of dihydrodipicolinate in sporulating Bacillus subtilis I. Purification and properties. 23 91

Two glycopeptides with identical amino acid sequence and carbohydrate composition, but of different sialic acid content were isolated from a combined tryptic-chymotryptic hydrolysate of bovine fibrinogen. Glycopeptide 1 contained two moles, glycopeptide 2 one mole of sialic acid. Both of them may have been derived from the gamma-polypeptide chain according to their amino acid sequence: Gln-Val-Glu-Asn-Lys.
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PMID:Heterogeneity in the carbohydrate moiety of the gamma-chain of bovine fibrinogen. 51 10

The ATP-energy transducing system in membranes of Escherichia coli is inhibited by dicyclohexylcarbodiimide. The protein component of this complex with which carbodiimides covalently react to inhibit function was previously identified by labeling wild type and dicyclohexylcarbodiimide-resistant mutants with dicyclohexyl[14C]carbodiimide (Fillingame, R. H. (1975) J. Bacteriol. 124, 870-883). This specific carbodiimide-reactive protein has now been purified. The protein was extracted from the membrane with chloroform:methanol and chromatographed on DEAE-cellulose and hydroxypropyl Spehadex G-50 in this sulvent mixture. The resultant 700-fold purification yielded a protein that was homogeneous on dodecyl sulfate-acrylamide gel electrophoresis and virtually free of phospholipid. It remained soluble in neutral chloroform:methanol throughout the purification procedure. The amino acid composition of the purified protein was extraordinary in that only 16% of the amino acids present could be considered polar. Histidine, serine, cysteine, and tryptophan were not found. Abnormally high contents of methionine, glycine, alanine, and leucine were present. One mole of lysine and threonine were found/mole of dicyclohexyl[14C]carbodiimide bound. The minimum molecular weight based on the amino acid composition was 8400. The specific carbodiimide-reactive protein has also been purified without prior modification by dicyclohexylcarbodiimide. The unmodified protein eluted from DEAE-cellulose at a higher salt concentration than the dicyclohexylcarbodiimide-modified form, which suggested that the reaction with the carbodiimide neutralized the negative charge. Only one-third of the total carbodiimide-reactive protein in the membrane was modified by dicyclohexylcarbodiimide under conditions which maximally inhibited adenosine triphosphatase activity. These results rais the possibility that the carbodiimide-reactive protein may be present as an oligomer in the energy-transducing complex. The purification of the unmodified carbodiimide-reactive protein should permit assessment of tis biological function, particularly its role in the protein-translocation process that is catalyzed by this energy-transducing complex.
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PMID:Purification of the carbodiimide-reactive protein component of the ATP energy-transducing system of Escherichia coli. 78 71

UDPglucose dehydrogenase from Escherichia coli has been purified 330-fold with an overall yield of 27%. A single homogeneous subunit was demonstrated by ultracentrifugation in 6 M guanidium chloride and by dodecyl sulfate-polyacrylamide gel electrophoresis. Since the molecular weight of the intact dehydrogenase is in the order of 86 000 and the subunit weight determined by the dodecyl sulfate-polyacrylamide gel electrophoresis is 47 000, the enzyme consists of two polypeptide chains. The sole amino terminal acid shown by the dansylation technique was arginine. Forty-four tryptic peptides were obtained by peptide mapping, in agreement with the number of arginine and lysine residues/mole protein [43] determined by amino acid analysis. The data are consistent with the presence of two identical or very similar polypeptide chains in E. coli UDPglucose dehydrogenase.
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PMID:UDP-glucose dehydrogenase from Escherichia coli. Purification and subunit structure. 79 22

Methods are described for the purification of a heparin-neutralizing protein from human platelets. The protein, obtained by conventional or affinity chromatographic techniques, is homogeneous by disc and sodium dodecyl sulfate gel electrophoresis, immunoelectrophoresis, and gel electrofocusing and can be obtained in a final yield of 75%. The protein has a subunit molecular weight of 9600, an isoelectric point at pH 7.6, and 18% basic and 22% acidic amino acid residues. The purified heparin-neutralizing protein forms dissociable complexes with heparin as measured by electrophoretic and Millipore filtration techniques employing [3H]heparin. The ability of a series of sulfated glycosaminoglycans to displace [3H]heparin from the binding protein was compared. The mole ratios required were: heparin less than heparan sulfate less than dermatan sulfate less than chondroitin 6-sulfate less than chondroitin 4-sulfate. Although the degree of sulfation of the aminoglycans correlated with the ability to displace [3H]heparin, the conformation fo the carboxyl group of the uronic acid and the location of the sulfate groups on the amino sugar also influenced the affinity for the protein. Evidence is also presented that binding to aminoglycans occurs via ionic interactions between lysine residues on the protein and negatively charged groups on the aminoglycan. Chemical modification of lysines by guanidination decreased heparin-neutralizing and binding activity, while modification of arginine residues had no effect. Heparin could prevent lysine modification when specifically bound to the heparin-neutralizing protein, but did not prevent lysine modification of other proteins.
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PMID:Purification and binding properties of human platelet factor four. 81 38

The third component of complement has been purified from fresh human plasma employing an initial fractionation with poly(ethylene glycol) followed by sequential depletion of plasminogen by affinity adsorbents, chromatography on diethylaminoethylcellulose, gel filtration on agarose, and batch adsorption/desorption on hydroxylapatite. Final recoveries of C3 were 33% of the initial protein, as quantitated by radial immunodiffusion, and 31% of the initial hemolytic activity. Apparent homogeneity is indicated by immunological criteria and by polyacrylamide gel electrophoresis. A partial specific volume of 0.736 +/- 0.003 mlgm-1 was determined for C3 by the mechanical oscillator technique. "Low speed" sedimentation equilibrium yielded an apparent weight average molecular weight for the protein of 187 650 +/- 5650. Based upon this molecular weight, a molar extinction coefficient of 1.82 X 10(5) 1. mole-1 cm-1 at 280 nm was calculated from boundary-spreading experiments in the ultracentrifuge and as assumed refractive index increment. Amino acid analyses revealed no unusual or distinctive characteristics. Automated Edman degradation revealed a double N-terminal sequence, Ser-Val,Pro-Glx,Met-Lee,Tyr-Thr,Ser-Glx,Ile-Lys,Gly-Arg,Thr-Met,Pro-Asx, in agreement with the two chain structure observed on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, and revealing both chains are available to degradation. Serine is postulated as the initiating sequence in both chains based upon high recoveries of dinitrophenylserine upon hydrolysis of dinitrophenylated C3, and our inability to identify any other dinitrophenyl or phenylthiohydantoin derivatives in this position. Alanine is the ultimate carboxy-terminal amino acid of at least one of the chains, as indicated by the action of carboxypeptidases on C3 in the presence of sodium dodecyl sulfate.
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PMID:Third component of human complement: purification from plasma and physicochemical characterization. 82 64

A procedure for the preparation of highly purified pig prothrombin is described. Compared to the initial clotting activity of the starting plasma, this protein was purified 776 times with a final yield of 8 per cent. The purified zymogen showed a specific activity of 1,460 NH units/mg of protein , a molecular weight of 65,000 as determined by SDS-polyacrylamide disc gel electroesis, E 1.0 mg/ml 1.0 cm, 280 nm = 1.45 at pH 7.0 and the following amino acid composition: Asx 51, Thr 38, Glx 62, Pro 23, Gly44, Ala 25, Half-Cys 30, Val 35, Met 3, Ile 30, Leu 32, Tyr 19, Phe 22, Lys 36, His 8, Arg 28, and Trp 13, which accounts for a minimum molecular weight of 59,370 (carbohydrates not computed). Alanine was found as the only N-terminal residue. Carboxypeptidases A and B failed to release any C-terminal residue. By hydrazinolysis however 0.4 mole of serine was released per mole of prothrombin. The activation of crude and chromatographed pig prothrombin was investigated.
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PMID:Pig prothrombin: purification and properties. 95 54

The number of combining sites per mole of bovine colostral anti-DNP IgG2 was found to be 2 and the total affinity constant was 0.81 X 10(4) M-1. Unlike bovine colostral IgG1, the nonspecific binding of H3-epsilon-DNP-1-lysine by IgG2 as a function of increased concentrations, did not show a negative, cooperative slope. Spectral measurements made with anti-DNP IgG2 in the reference cell vs. anti-DNP IgG2 plus hapten in the experimental cell revealed a hypochromic, red shift from 363 to 365 nm. If the reference cell contained hapten, a red shift from 280 to 283 nm and an enhancement in the extinction coefficient of IgG2 was observed. These spectral changes were not observed if nonspecific IgG2 was substituted for anti-DNP IgG2 in the experimental cell. The enhancement in the extinction coefficient was interpreted to be due to a possible exposure of previously buried tryosine and tryptophan residues.
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PMID:Binding properties of bovine colostral anti-dinitrophenyl (dnp) immunoglobulins g2 (igg2). 99 4

Intracellular perfusion of giant axons from Loligo forbesi with a crude protein extract of Pronase dissolved in a KF solution suppresses the process of fast inactivation of the Na conductance (the h-process in the Hodgkin-Huxley terminology). 2. The results with protease inhibitors indicate that the most substrate specific endopeptidase present in pronase, alkaline proteinase b, destroys the h-process. 3. After destruction of the inactivation the conductance rise upon depolarization followed cube law kinetics. Values of the time constant taum before and after destruction of the h-process were very similar. 4. After destruction of the inactivation process the following properties were tested: cation selectivity, instantaneous conductance and internal receptor sites for tetrodotoxin (TTX) and tetraethylammonium (TEA). No detectable changes in selectivity or instantaneous conductance were observed. No internal receptors for TTX affecting the Na conductance were found but a TEA receptor is exposed by the protein hydrolysis. 5. TEA derivatives (triethylammonium, TEA-, with an aliphatic chain, Cn) induce a partial block of the steady-state sodium current and induce a time-dependent blockage of the conductance. 6. The first effect of TEA-Cn could be described in terms of a unimolecular reaction with the following equilibrium constants: 50, 2-5, 1-0, 0-4 and 0-025 mM for TEA-C2, TEA-C4, TEA-C5, TEA-C7 and TEA-C9 respectively. 7. From the dependence of the equilibrium dissociation constant on the length of the alkyl chain we estimated the free-energy change in 560 cal/mole of CH2. The gain in free energy per CH2 group transferred from aqueous medium to the interior of a non-polar medium is 1000 cal. 8. Although with the data at hand it is impossible to propose the amino-acid sequence of the site cleaved by alkaline proteinase b, we propose that an important functional component is arginine (or lysine).
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PMID:Destruction of the sodium conductance inactivation by a specific protease in perfused nerve fibres from Loligo. 99 46


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