Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The chromatin core particle DNA conformation deduced in broad outline by Finch et al. [Finch, J. T., Lutter, L. C., Rhodes, D., Brown, R. S., Rushton, B., Levitt, M. & Klug, A. (1977) Nature 269, 29-36] can be described in detail using other available experimental results. Histone binding sites compatible with the pattern of pancreatic DNase I digestion (Simpson, R. T. & Whitlock, J. P., Jr. (1976) Cell 9, 347-353; Noll, M. (1977) J. Mol. Biol. 116, 49-71; Lutter, L. C. (1977) J. Mol. Biol. 117, 53-69] lend to core particle DNA pseudosymmetry characteristic of molecular point group D(3). DNA symmetry and pseudosymmetry, in turn, imply equivalence and quasi-equivalence properties of the histone packing arrangement that support the following deductions: (i) One and only one alpha(2)beta(2) histone tetramer, presumably (H3)(2)(H4)(2), can serve as a stable subassembly within the histone octamer. (ii) There is a unique, strand-specific way to assign DNA binding domains to the arginine-rich histones (H3 and H4). (iii) Histones H3 and H4 alone should suffice to impose a supercoiled structure on DNA, as is observed experimentally, because only the tetramer can mimic a screw dislocation and thereby complement the screw symmetry of the DNA supercoil. (iv) The two slightly lysine-rich histones H2A and H2B are probably responsible, each in a different way, for dividing the eukaryotic chromatin fiber into discrete subunits. (v) The proposed arrangement of four distinct proteins appears to be a minimum formal requirement for making nucleosomes; that is, for introducing regularly spaced supercoiled DNA folds without also allowing formation of an indefinitely long (and genetically inert) DNA superhelix.
 ...
PMID:Histone packing in the nucleosome core particle of chromatin. 27 80

Paracatalytic enzyme modifications result from the oxidation of enzyme-substrate carbanions by extrinsic oxidants. During the oxidation of enzyme-activated substrates, transiently reactive intermediates are generated which, without being released from the enzyme, modify groups at the active site. For enzymes producing carbanion intermediates, the combination of the normal substrate with a suitable electron acceptor has thus been proposed as a highly specific binary system for their active site-directed modification. In this study, the structural features of paracatalytically modified fructose-1,6-bisphosphate aldolase (D-fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphate lyase, EC 4.1.2.13) from rabbit muscle have been elucidated. This enzyme is completely inactivated within 60 min in the presence of fructose 1,6-bisphosphate in saturating concentration and 0.5 mM hexacyanoferrate(III) (pH 7.6, 25 degrees C). The inactivation is caused by covalent incorporation of one triosephosphate derivative per subunit. Peptide analysis showed that the triosephosphate derivative forms an intrachain crosslink between lysine-146 and lysine-227. According to previous independent experimental evidence, both lysyl residues are located at the active site: the epsilon-amino group of lysine-227 forms a Schiff base intermediate with the carbonyl group of the substrate [Lai, C. Y., Nakai, N. & Chang, D. (1974) Science 183, 1204-1206] and alkylation of lysine-146 by the affinity labeling reagent N-bromoacetylethanolamine phosphate inactivates the enzyme [Hartman, F. C. & Brown, J. P. (1976) J. Biol. Chem. 251, 3057-3062]. The present data thus establish paracatalytic modification as a mode of active site-directed enzyme modification.
 ...
PMID:Paracatalytic modification of aldolase: a side reaction of the catalytic cycle resulting in irreversible blocking of two active-site lysyl residues. 28 42

A phospholipase A2 was purified from the Mexican coral snake Micrurus fulvius microgalbieus (Brown and Smith). Gel filtration of the soluble crude venom on Sephadex g-50 resolved five fractions, of which fraction II had 98% of the total phospholipase activity. This fraction was rechromatographed on a CM-cellulose column that resolved eight fractions, four of which had an important phospholipase activity. The first fraction (II-1) was homogeneous by polyacrylamide-gel electrophoresis and displayed a phospholipase specific activity of 920 units/mg of protein. The apparent molecular weight as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis was approx. 14000. The amino acid analysis revealed the presence of 119 amino acid residues, with 12 half-cystines. the N-terminal sequence was shown to be Ser-Leu-Leu-Asx-Phe-Lys-Asx-Met-Ile-Glu-Ser-Thr..., which is homologous with that of phospholipases from other snake venoms.
 ...
PMID:Purification and characterization of a phospholipase A2 from the venom of the coral snake, Micrurus fulvius microgalbineus (Brown and Smith). 47 71

Heparin cofactor II (HC) is a plasma serine proteinase inhibitor (serpin) that inhibits the coagulant proteinase alpha-thrombin. We have recently demonstrated that proteolysis of HC by catalytic amounts of polymorphonuclear leukocyte proteinases (elastase or cathepsin G) generates leukocyte chemotaxins (Hoffman, M., Pratt, C. W., Brown, R. L., and Church, F. C. (1989) Blood 73, 1682-1685). One of four peptides produced when HC is degraded by neutrophil elastase has chemotactic activity for both monocytes and neutrophils with maximal migration comparable to formyl-Met-Leu-Phe, the "gold standard" bacterially derived chemotaxin. The amino-terminal sequence of this HC peptide is Asp-Phe-His-Lys-Glu-Asn-Thr-Val-... and the peptide corresponds to Asp-39 to Ile-66 of HC. A variety of synthetic peptides derived from this sequence were evaluated for leukocyte migration activity, and a dodecapeptide from Asp-49 to Tyr-60 (Asp-Trp-Ile-Pro-Glu-Gly-Glu-Glu-Asp-Asp-Asp-Tyr) was identified as the active site for leukocyte chemotactic action. The 12-mer synthetic peptide possesses significant neutrophil chemotactic action at 1 nM (60% of the maximal activity of formyl-Met-Leu-Phe), while a peptide with the reverse sequence has essentially no chemotactic activity. Cross-desensitization experiments also show that pretreatment of neutrophils with a 19-mer peptide (Asn-48 to Ile-66) greatly reduces subsequent chemotaxis to HC-neutrophil elastase proteolysis reaction products. When injected intraperitoneally in mice, the HC-neutrophil elastase digest elicits neutrophil migration. Our results demonstrate that not only does HC function as a thrombin inhibitor, but that limited proteolysis of HC near the amino terminus yields biologically active peptide(s) which might participate in inflammation and in wound healing and tissue repair processes.
 ...
PMID:Leukocyte chemoattractant peptides from the serpin heparin cofactor II. 198 58

Tryptophyl-tRNA synthetase is irreversibly inactivated by Procion Brown MX-5BR with an apparent dissociation constant (KD) of 8.8 microM and maximum rate of inactivation k3 0.192 s-1. The specificity of the interaction is supported by two previously reported observations. Firstly, Brown MX-5BR inactivation of tryptophyl-tRNA synthetase is inhibited by substrates, and secondly, the animated derivative of Brown MX-5BR is a competitive inhibitor of tryptophyl-tRNA synthetase with a Ki of 2 X 10(-4) M with respect to both tryptophan and ATP. Tryptic digestion of the dye-affinity-labelled enzyme and subsequent resolution of the peptides by h.p.l.c. yielded one major dye-peptide peak. Amino acid sequence analysis resulted in the identification of the dye-binding domain centred on lysine-178. Tyrosyl-tRNA synthetase is also inactivated by Procion Brown MX-5BR, and this inactivation is prevented by ATP but not by tyrosine. The interaction of tyrosyl-tRNA synthetase with hydroxylated Brown MX-5BR exhibited non-competitive kinetics with respect to the amino acid-binding site and competitive kinetics against ATP with a Ki of 6 X 10(-6) M.
 ...
PMID:The isolation of a peptide from the catalytic domain of Bacillus stearothermophilus tryptophyl-tRNA synthetase. The interaction of Brown MX-5BR with tyrosyl-tRNA synthetase. 366 97

Single capillaries in the mesenteries of pithed frogs were perfused sequentially with two frog Ringer solutions. The first solution contained no protein; the second solution contained either native or chemically modified bovine serum albumin (BSA) at a concentration of 3-5 mg ml-1. During each perfusion capillary permeability was assessed from the hydraulic conductivity of the capillary wall (Lp) which was determined from measurements of fluid filtration rate at two or more different capillary pressures (Michel, Mason, Curry, Tooke & Hunter, 1974). Lp measured during perfusion with protein-free Ringer solution was on average three times greater than its value for the same vessel perfused with Ringer solution containing native BSA. This confirms the findings of Mason, Curry & Michel (1977). BSA, which had been succinylated to modify the free amino groups of its lysine residues, appeared to be as effective as native BSA in reducing Lp. After modification of its arginine side chains by exposure to 1,2-cyclohexanedione (CHD) in the presence of 0.2 M-NaOH, BSA lost its property of reducing Lp in capillaries perfused with Ringer solution. Exposure of BSA to 0.2 M-NaOH followed by dialysis against normal Ringer solution did not affect its property of reducing Lp. CHD-treated BSA at a concentration of 2.5 mg ml-1 had no effect upon the effective osmotic pressure exerted across capillary walls by Ringer perfusates containing the neutral polymer Ficoll 70 at a concentration of 40 mg ml-1. Native BSA raised the effective osmotic pressure from 7.07 +/- 1.93 cmH2O to 20.50 +/- 2.37 cmH2O (n = 7; P less than 0.001). It is concluded that the effects of BSA on permeability depend upon specific sites in the BSA molecule. It is suggested that these sites involve positively charged arginine side chains of the albumin molecule. The results are discussed in terms of the fibre-matrix hypothesis of capillary permeability and in terms of Brown's (1976) theory for the structure of albumin.
 ...
PMID:The effects of native and modified bovine serum albumin on the permeability of frog mesenteric capillaries. 392 91

Lewis (LEW) rats immunized 3 weeks before by injection of DNP-KLH together with Bordetella pertussis showed high levels of DNP antibody as judged by serum binding of 10(-7) M 3H-DNP-lysine 10 days after secondary immunization with DNP-KLH. Sera obtained from LEW rats following secondary immunization with DNP-BGG showed reduced DNP hapten binding. However, injection of 10(8) F1 hybrid Lewis X Brown Norway spleen cells into DNP-primed LEW rats 2 days before secondary immunization with DNP-BGG significantly increased the level of serum binding of 3H-DNP-lysine. These results provide evidence that the allogeneic cellular reaction associated with a host-versus-graft response induced by injection of F1 hybrid lymphoid cells into DNP-primed parental strain recipients partially obviates the requirement for carrier-specific T cells in the secondary anti-DNP response thereby providing a stimulus for triggering primed host B cells to produce antibody.
 ...
PMID:Hapten antibody production and the relevance of allogeneic reactions to elimination of the carrier effect. 615 32

The complete amino acid sequences of the alpha and beta subunits of allophycocyanin from the unicellular rhodophyte, Cyanidium caldarium, were determined by automated Edman degradation of the proteins and peptides derived from them by chemical and enzymatic cleavages. The sequence of the alpha subunit was determined from the sequences of tryptic, endoproteinase lysine-C, and cyanogen bromide peptides and carboxypeptidase A and Y digestion of the protein. The sequence of the beta subunit was determined from the sequences of tryptic, endoproteinase lysine-C, Staphylococcus aureus V8 protease, and cyanogen bromide peptides and in addition, a peptide derived from acid cleavage of an aspartyl-prolyl bond. The carboxyl-terminal sequence of the protein was determined by digestion with carboxypeptidase A. The alpha subunit contains 160 amino acids, one phycocyanobilin chromophore attached at residue 80 by a cysteinyl-thioether linkage, and the Mr calculated from the sequence is 18,160. The beta subunit contains 161 amino acids, one phycocyanobilin chromophore attached at residue 81 by a cysteinyl-thioether linkage, and the Mr calculated from the sequence is 18,125. The amino acid sequences of the alpha and beta subunits of allophycocyanin from C. caldarium are the first complete amino acid sequences of an allophycocyanin from a eukaryotic red alga. A matrix comparison of the alpha and beta subunits of C. caldarium allophycocyanin and phycocyanin (Offner, G.D., Brown-Mason, A.S., Ehrhardt, M. M., and Troxler, R. F. (1981) J. Biol. Chem. 256, 12167-12175; Troxler, R. F., Ehrhardt, M. M., Brown-Mason, A. S., and Offner, G. D. (1981) J. Biol. Chem. 256, 12176-12184) shows homology ranging from 26 to 39%. Comparison of the sequences of alpha and beta subunits of C. caldarium allophycocyanin with the sequences of the corresponding subunits of allophycocyanin from two prokaryotic cyanobacteria (Sidler, W., Gysi, J., Isker, E., and Zuber, H. (1981) Hoppe-Seyler's Z. Physiol. Chem. 362, 611-628; DeLange, R. J., Williams, L. C. and Glazer, A. N. (1981) J. Biol. Chem. 256, 9558-9566) shows homology ranging from 81 to 85%. The significance of this with respect to phycobiliprotein structure and function is discussed.
 ...
PMID:Primary structure of allophycocyanin from the unicellular rhodophyte, Cyanidium caldarium. The complete amino acid sequences of the alpha and beta subunits. 688 76

Ten soybean varieties with colored seed coats were evaluated in Jaboticabal, with the objective of obtaining information as to color preference in the direct use of soybeans in human consumption. The above-mentioned material showed good adaptation to the local environmental conditions: plant cycles were smaller than the Santa Rosa (121 days), varying from 107 to 119 days, in spite of the fact that some varieties started blooming later than Santa Rosa. All materials are within the minimum standards for local planting; however, some of them showed a lodging problem, and all varieties are susceptible to bacterial pustule. They have smaller seeds than Santa Rosa, and in relation to yield, varieties as the NC-55, Aksarben 1S (Black), Aksarben 1S (Brown) and Chi kei 13 did not statistically differ from the Santa Rosa. Protein content showed a variability of 37.90 to 43.90% and oil varied from 14.72 to 21.34%. Methionine content was between the known limits (0.907 to 1.644 g/16 g N), but lysine was higher than any reported data (7.584, to 10.877 g/16g N). The Tanner, Chi kei 13 and Chi kei 15 presented a high percentage of hard beans. This fact had a positive influence on the seed hydration characteristics, but their experimental cooking times were very low, varying from 51 and-a-half to 122 minutes. The term "hydration time" is being introduced here, which is defined as the time, in hours, required for a seed to double up its weight when submerged in water.
 ...
PMID:[Agronomic, nutritional and processing characteristics of soybean germ plasm with colored seed coats]. 720 2

Allophycocyanin from Nostoc sp. phycobilisomes was separated into four spectrally distinct components designated allophycocyanin I, B, II, and III by adsorption chromatography on brushite columns. Allophycocyanins I and B had red-shifted fluorescence emission maxima, and on this basis, may function in transfer of excitation energy from phycobilisomes to chlorophyll a. Allophycyanins II and III, which together comprise 70% of the total allophycocyanin, have absorption maxima at 648 nm and 650 nm, respectively, and probably transfer excitation energy from phycocyanin to allophycocyanins I and B, in addition to serving a structural function. Allophycocyanin I was resolved into alpha, beta, and gamma subunits with apparent molecular weights of 18,000, 17,000, and 35,000, respectively, whereas allophycocyanin B was resolved into two subunits with apparent molecular weights of 16,100 and 15,300, using a modified Weber and Osborn gel electrophoresis system (Brown, A. S., and Troxler, R. F. (1977) Biochem. J. 163, 571-581). In the same gel system, allophycocyanins II and III were each resolved into alpha and beta subunits with apparent molecular weights of 18,000 and 17,000, respectively. The subunits of allophycocyanins I, II, and III were isolated by gel filtration and ion exchange chromatography and the amino acid compositions determined. Automated sequence analysis demonstrated that the first 30 amino acids at the NH2 terminus of alpha subunits, and the beta subunits, of allophycocyanins I to III were identical. alpha Subunits: Ser-Ile-Val-Thr-Lys-Ser-Ile-Val-Asn-Ala-Asp-Ala-Glu-Ala-Arg-Tyr-Leu-Ser-Pro-Gly -Glu-Leu-Asp-Arg-Ile-Lys-Ser-Phe-Val-Thr- beta Subunits: Ala-Gln-Asp-Ala-Ile-Thr-Ala-Val-Ile-Asn-Ala-Ala-Asp-Val-Gln-Gly-Lys-Tyr-Leu-Asp-Ala-Thr-Ala-Leu-Ser-Lys-Leu-Lys-Ala-Tyr- The gamma subunit of allophycocyanin I and both subunits of allophycocyanin B appeared to be blocked at the NH2 terminus, suggesting that the allophycocyanin B subunits may be different gene products than those of allophycocyanins I to III, or if the same, the subunits of allophycocyanin B undergo proteolytic modification after initial synthesis.
 ...
PMID:Allophycocyanin from Nostoc sp. phycobilisomes. Properties and amino acid sequence at the NH2 terminus of the alpha and beta subunits of allophycocyanins I, II, and III. 741 Apr 30


1 2 3 4 5 6 Next >>