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)

In vitro lysis of fibrin, as indicated by increased fibrinogen-fibrin-related antigen (FR-antigen) in serum is usually seen when whole blood, or plasma, or highly purified fibrinogen prepared by several different procedures is clotted and kept at temperatures above 0 degrees C. This increase is both time and temperature dependent, occurs despite the addition of various plasmin and cathepsin inhibitors, and is probably caused by thrombin evolved during clotting and/or added in vitro. In these experiments, the FR-antigen was measured by a sensitive, reproducible hemagglutination inhibition immunoassay adapted to the AutoAnalyzer. Serum from whole blood contained more than serum from plasma, and fibrin rather than fibrinogen proved to be essential for the in vitro lysis. The phenomenon was also caused by Arvin or Reptilase, suggesting that splitting of one or more arginine or lysine bonds in fibrin may be at least partially responsible. To obtain minimal levels of FR-antigen (< 0.5 mug/ml), plasma is clotted for 4 hr at 0 degrees C with 1.0-5.0 U/ml thrombin, CaCl(2) (0.0125 mole/liter), and epsilon aminocaproic acid (0.05 mole/liter). Slightly higher levels, probably adequate for clinical diagnosis, are obtained by 10-30 min clotting at room temperature. Since endogenous and/or exogenous thrombin is essential for the collection of serum FR-antigen, all the FR-antigen found in normal serum probably results from an irreducible amount of in vitro lysis rather than from continuous intravascular clotting and fibrinolysis.
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PMID:Increase in fibrinogen and fibrin-related antigen in human serum due to in vitro lysis of fibrin by thrombin. 501 17

Uptake of l-valine by germinated spores of Arthrobotrys conoides has all the characteristics of a system of transport that requires an expenditure of energy by the cells. It is dependent on temperature and has an energy of activation of 16,000 cal/mole. Uptake is optimal at pH 5 to 6. l-Valine accumulated against a concentration gradient and is not lost from the cells by leakage or exchange. The process requires energy supplied by the metabolic reactions that are inhibited by catalytic amounts of 2,4-dinitrophenol and azide. The kinetics of the system are consistent with a mechanism of transport that depends on a limited number of sites on the cell surface, and the Michaelis constant for the system is 1.5 x 10(-5) to 7.5 x 10(-5)m. Modification of the amino or carboxyl group abolishes l-valine uptake. The process is competitively inhibited by d-valine, glycine, and other neutral amino acids (K(i) = 1.5 x 10(-5) to 4.0 x 10(-5)m), indicating a lack of stereospecificity, and also indicating that aliphatic side chain is not required for binding with the carrier. The transport system has less affinity for acidic amino acids (glutamic and aspartic acids) than neutral amino acids, and a greater affinity for basic amino acids (histidine, lysine, and arginine). The range of affinity is in the order of 100, as measured in terms of K(i) values for various compounds. The data presented provide suggestive evidence that the uptake by A. conoides of all amino acids except proline is mediated by a single carrier system that possesses an overall negative charge.
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PMID:Amino acid transport by the filamentous fungus Arthrobotrys conoides. 546 78

To study the nature of the antigen-antibody complexes which initiate the specific wheal-and-flare (W & F) reaction in sensitized man, a homologous series of bivalent, oligovalent, and multivalent benzylpenicilloyl (BPO) haptens were quantitatively compared for their effectiveness in eliciting W & F in BPO-sensitized human subjects.A series of seven divalent haptens were capable of eliciting W & F, but these generally were not maximally effective elicitors. Of the divalent haptens, those with separation chains of 8 or 13 A were the most effective. Of the oligovalent haptens, maximal effectiveness was attained with BPO(6)-lysine(7), and not with BPO(2)-lysine(3) or BPO(4)-lysine(4), i.e., haptens which are 6- 3- and 4-valent, respectively, from a chemical point of view. However, evidence was obtained from quantitative precipitation experiments which indicated that BPO(6)-lysine(7) functions as a trivalent hapten immunologically, i.e., capable of binding three antibody molecules per mole hapten. Large molecularsized haptens with immunological valences of 7 or 12, but in which the haptenic groups were widely separated, were comparatively ineffective elicitors of W & F. In individual subjects, threshold W & F reactions were obtained with equimolar concentrations of the differently sized divalent, oligovalent, and multivalent haptens. The results demonstrate that for maximally effective elicitation of W & F by haptens, trivalency with optimal distances of separation of haptenic groups is necessary and sufficient. These results indicate the requirement for the formation of a high energy complex of two or three membrane-fixed skin-sensitizing antibody molecules closely bridged together by the elicitor hapten as the initiator of the W & F reaction.
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PMID:The nature of the antigen-antibody complexes initiating the specific wheal-and-flare reaction in sensitized man. 563 43

1. The molecular weight of porcine neurophysin was estimated by molecular sieve chromatography and by analytical ultracentrifugation and was found to be in the order of 13,000.2. Internal evidence for the homogeneity of the preparation of neurophysin with respect to molecular weight was obtained in the ultracentrifugation experiments.3. The frictional ratio of neurophysin was 1.1 which suggests that the molecular form of the protein approximates to a sphere.4. The molecular weight and frictional ratio were not affected by temperature change (10-34 degrees C) or by twofold change in protein concentration.5. The binding of [(14)C]lysine vasopressin to porcine neurophysin was studied at 0, 27 and at 45 degrees C, and double reciprocal plots of the binding were shown to be curvilinear at 27 and at 45 degrees C and rectilinear at 0 degrees C.6. Concordant estimates for maximum binding capacity were obtained by extrapolations from the data at 27 and 45 degrees C by applying two independent empirical methods of approximation; these agreed with the estimate obtained by extrapolation of the straight line, fitting data obtained at 0 degrees C, being approximately 1 mole lysine vasopressin per 13,000 g protein.7. The association constant and thermodynamic parameters of the reaction were estimated for near saturation conditions. The reaction is entropy driven.8. The binding of lysine vasopressin was found to be dependent on protein concentration. No dependence of oxytocin binding on protein concentration was apparent.
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PMID:The molecular dimensions of porcine neurophysin and some thermodynamic parameters of the reaction with lysine vasopressin. 577 52

1. Inhibition of ox liver glutamate dehydrogenase with N-(N'-acetyl-4[(35)S]-sulphamoylphenyl)maleimide (ASPM) is more specific at pH7.3 than at pH6.9. At pH7.3 inhibition accompanies the incorporation at 1 mole of ASPM residues into about 53000g. of protein. 2. Digestion of the modified protein with chymotrypsin and trypsin yields a unique radioactive peptide. 3. Acid hydrolysis of 1 mole of this peptide yields 1 mole of N(in)-succin-2-yl-lysine. The in-amino group of a lysyl residue is thus the site of modification of the protein. 4. The sequence containing the modified lysyl residue is: [Formula: see text] where Asx respresents either aspartic acid or asparagine.
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PMID:A peptide containing a reactive lysyl group from ox liver glutamate dehydrogenase. 578 69

Mucopeptides isolated from Streptococcus bovis cell walls were found to be composed of alanine, glutamic acid, lysine, and threonine in a mole ratio of 3:1:1:1. A dipeptide, N(epsilon)-lysylthreonine, was isolated from S. bovis mucopeptide by ion-exchange chromatography. This finding suggests that threonine is associated with the bridge which cross-links adjacent tetrapeptides by connecting the epsilon-amino group of lysine of one tetrapeptide to the carboxyl group of d-alanine of another to form the mucopeptide matrix.
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PMID:Chemical studies on the structure of mucopeptide isolated from Streptococcus bovis. 580 3

Streptococcal mucopeptide, solubilized by either ultrasonic treatment or lysozyme, gave a precipitin reaction with rabbit antimucopeptide serum. A haptenic inhibitor of this reaction, which was composed of alanine, glutamic acid, and lysine in a mole ratio of 4:1:1, was isolated from a Streptomyces albus enzymes digest of Group D cell walls by ion exchange chromatography. When selected antisera were employed, greater than 90% inhibition of the mucopeptide quantitative precipitin reaction was achieved with 2 mg/ml of this inhibitor, whereas a hexosamine fraction with minimal concentrations of amino acid residues was inactive in this respect. These results suggest that the peptide moiety is an antigenic determinant of mucopeptide. Preliminary results indicate that the hexosamine polymer of the mucopeptide is a secondary antigenic determinant.
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PMID:Studies on the immunochemistry of streptococcal mucopeptide. 591 89

Cell walls were isolated by mechanical disruption of mid-log phase cells of Bacillus stearothermophilus NCA 1503-4R grown in Trypticase-yeast extract-fructose medium at 55 C. The cell walls were purified by treatment with sodium dodecyl sulfate (SDS) and incubation with deoxyribonuclease and trypsin. The cell wall peptidoglycan contained glucosamine, muramic acid, alpha, epsilon-diaminopimelic acid, and glutamic acid. Low amounts of glycine, galactosamine, serine, aspartic acid, lysine, and valine were also present. The relative mole ratios of glutamic acid-alpha, epsilon-diaminopimelic acid-glycine-alanine were 1.00:1.26:0.08:1.55. The cell walls were free from ribonucleic acid and deoxyribonucleic acid and contained less than 0.2% chloroform-methanol extractable lipid and 0.09 mumole of phosphorus per mg of cell wall. Teichoic acid was not detected in the cell walls of this organism. Cell walls isolated without treatment with SDS contained 7.5% chloroform-methanol extractable lipid, 0.24 mumole of phosphorus per mg of cell wall, and relatively high concentrations of all amino acids. These results suggest that the extracted lipid is not a cell wall component per se, but a contaminant from the lipoprotein cell membrane.
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PMID:Chemical composition of the cell walls of Bacillus stearothermophilus. 603 16

Human liver alanine aminopeptidase (EC 3.4.11.14; L-alpha-aminoacyl-peptide hydrolase) catalyzes the stepwise hydrolysis of methionyl-lysyl-bradykinin to yield methionine, lysine, and the limit nonapeptide, bradykinin which is resistant to further hydrolytic cleavage by this enzyme. Alanine aminopeptidase also catalyzes the hydrolysis of various neutral amino acid beta-naphthylamides. This enzyme cleaves N-terminal arginyl residues unless the adjacent penultimate residue is proline as is the case for bradykinin. The properties are consistent with the requirements of a kinin converting enzyme. Human alanine aminopeptidase activity is reduced by several beta-lactam antibiotics, with the cloxacillin, oxacillin, and methicillin Ki values being 0.51 mM, 1.6 mM, and 2.4 mM respectively. Our experiments with radioactively labelled penicillin indicate that two moles of antibiotic are bound per mole of enzyme. Neither chromatography of the penicillin-treated enzyme on G-25 Sephadex, treatment of penicillin-G-treated enzyme with penicillinase, nor extensive dilution of cloxacillin-treated enzyme diminished the degree of inactivation produced. Inhibition was obtained with 6-aminopenicillanic acid, which indicated that the penicillin nucleus itself was being bound, but substitutions, as in cloxacillin, could enhance the binding.
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PMID:Human-liver alanine aminopeptidase. A kinin-converting enzyme sensitive to beta-lactam antibiotics. 612 21

A theoretical model of charge and size selectivity for the glomerulus has been applied to human data. Using previously published values for GFR, renal plasma flow, systemic oncotic pressure, and fractional clearances of neutral dextrans, albumin, salivary amylase, and transferrin, membrane parameters describing the glomerular barrier were determined for normal individuals under control conditions and during lysine infusion (which retards tubule protein reabsorption), and for patients with minimal change nephropathy (MCN). To permit the estimation of membrane charge from fractional clearances, molecular charge values for human transferrin (-9.4 Eq/mole) and human salivary amylase (-4.1) were determined by measuring electrophoretic mobilities of these proteins in polyacrylamide gels. Assuming no large changes in the transmural hydraulic pressure difference (delta P), the glomerular ultrafiltration coefficient (Kf, the product of hydraulic permeability and capillary surface area) was calculated to be reduced by greater than 50% in MCN. The effective pore radius (approximately 55 A) is virtually unaltered in MCN, suggesting that the decline in Kf is due to a reduced number of pores. The degree of albuminuria observed in MCN is attributable to an approximately 50% reduction in the concentration of fixed negative charges in the glomerular capillary wall. The concentrations of fixed charges calculated from albumin data in normal individuals (140 to 160 mEq/liter) and in patients with MCN (60 to 90 mEq/liter) are insensitive to the assumed values of delta P.
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PMID:Glomerular charge alterations in human minimal change nephropathy. 618 37


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