Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:EXPT00572 (Asn)
 11,732 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The membrane penicillinase of Bacillus licheniformis 749/C has been demonstrated to be a phospholipoprotein. The homogeneous enzyme gives a positive reaction for phosphorous and for unsaturated fatty acids, has a molecular weight of 33,000 in contrast to 29,000 for the exoenzyme, and contains 8 to 9 additional residues of aspartate or asparagine, 4 to 5 of serine, 7 of glutamate or glutamine, and 4 to 5 of glycine per mole. The COOH-terminal sequence of both membrane and exoenzymes is -Met-Asn-Gln-Lys-COOH; hence the extra peptide portion present in the membrane enzyme is not attached to the COOH-terminus of the exoenzyme. Procedures which readily detected the lysine residue at the NH2 terminus of the exoenzyme did not yield a positive test with the membrane form. The NH2 terminus of the membrane enzyme may be blocked by or linked to the phospholipid. A procedure for the preparation of membrane penicillinase on a large scale and an improved method for purification of the exoenzyme have been developed.
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PMID:Purification of plasma membrane penicillinase from Bacillus licheniformis 749/C and comparison with exoenzyme. 0 71

The amide content of neocarzinostatin (NCS), an antitumor protein, has been determined by analysing asparagine and glutamine in the Pronase-aminopeptidase M digests of tetra-S-carboxymethyl-NCS and carboxyl-modified NCS (modified with a water-soluble carbodiimide and [14C]glycine methyl ester). Preneocarzinostatin (PRE) was separated and purified from a crude NCS preparation by CM-cellulose column chromatography. PRE was found to contain one mole less asparagine than NCS, and asparagine was deamidated to aspartic acid in PRE. A time-dependent conversion of NCS to PRE at pH 3.2 at 4 degrees or in 0.1 M acetic acid at 26 degrees was studied in two ways; first, by quantitative determination of NCS and PRE by CM-cellulose column chromatography and second, by following the release of free NH3 during dialysis in an air-tight container. Within experimental error, PRE was indistinguishable from NCS in amino acid content after acid hydrolysis, as well as in apparent molecular weight as determined by SDS-disc gel electrophoresis (10% acrylamide), and N- and C-terminal amino acid residues. Both NCS and PRE shared a common antigenicity as determined by Ouchterlony's agar diffusion method. Only a slight difference between the two in electrophoresis on a cellulose acetate membrane and on a peptide map of the tryptic digest was demonstrated. PRE, however, was completely devoid of biological activity. In addition to the chromatographic difference, a conformational difference was observed by CD spectroscopy, namely, an apparently looser structure of PRE was indicated by the shallowness of the trough in the 240-265 nm region. This interpretation was supported by the finding that digestions by Pronase were more extensive with PRE than with NCS. These results indicate an important role of the single asparagine residue (Asn 83) of NCS in the biological activity, which is evidently governed by the conformation.
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PMID:Spontaneous deamidation of a protein antibiotic, neocarzinostatin, at weakly acidic pH. Conversion to a homologous inactive preneocarzinostatin due to change of asparagine 83 to aspartic acid 83 accompanied by conformational and biological alterations. 1 34

The expression of asparagine synthetase activity [L-aspartate:ammonia ligase (AMP-forming), EC 6.3.1.1] in cultured Chinese hamster ovary (CHO) cells is regulated by asparagine. After transfer of CHO cells from an asparagine-supplemented medium to a medium lacking asparagine, activity increases 1.5- to 2-fold. If asparagine is added back to the medium, activity returns to control levels. To test the possible involvement of Asn-tRNAAsn in regulating the levels of asparagine synthetase, we have examined the levels of asparagine synthetase in a mutant of CHO cells containing a temperature-sensitive asparaginyl-tRNA synthetase [L-asparagine:tRNA ligase (AMP-forming), EC 6.1.1.22]. Under conditions of limited asparaginyl-tRNA synthetase activity in the mutant, there is a 2- to 3-fold increase in the level of asparagine synthetase activity. Under identical conditions, there is no change in asparagine synthetase activity in the wild type. This correlation between asparaginyl-tRNA synthetase activity and asparagine synthetase levels may be a consequence of a direct role of tRNAAsn in the regulation of the in vivo expression of the asparagine synthetase structural gene.
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PMID:A role for asparaginyl-tRNA in the regulation of asparagine synthetase in a mammalian cell line. 1 35

Hemoglobin G. Ferrara is an abnormal human hemoglobin in which an asparagine residue is replaced by a lysyl residue at position beta57 (beta57 Asn replaced by Lys). Oxygen equilibria show that cooperativity and alkaline Bohr effect are maintained to normal levels while the acid Bohr effect appears increased; in addition, a smaller effect of diphosphoglycerate is also observed. Flash photolysis experiments performed as a function of protein concentration show that the fraction of quickly reacting form is always higher than that of human hemoglobin A. This fact, together with the increase of the oxygen affinity observed at acid pH values, may be related to an enhanced dissociation of the molecule into dimers. Several attempts to isolate the native chains by treatment of the protein with p-chloromercuribenzoate were unsuccessful due to the great instability of the isolated variant beta-chains, which precipitated completely during incubation with p-chloromercuribenzoate. Therefore, although the substitution is on the surface of the molecule, there are several properties of hemoglobin G. beta Ferrara which are clearly different from hemoglobin A.
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PMID:Properties of hemoglobin G. Ferrara (beta57(E1) Asn replaced by Lys). 2 14

The Vicia angustifolia proteinase inhibitor was incubated with p-toluenesulfonyl-L-phenylalanine chloromethyl ketone-trypsin (EC 3.4.21.4) and a main product was isolated. The purified product was different to the first trypsin-modified V. angustifolia inhibitor. The C-terminal residues of the new derivative were arginine, which was also the C-terminal of the cleaved antitryptic site; lysine was a newly exposed C-terminal. These results suggest that the new derivative lacks the C-terminal portion of the native inhibitor, which has asparagine at its C-terminus. The liberated C-terminal peptide had the following amino acid sequence: H-Glu-Glu-Val-Ile-Lys-Asn-OH. The derivative lacking the C-terminal hexapeptide still possesses inhibitory activities against trypsin and alpha-chymotrypsin (EC 3.4.21.1), however, its antichymotryptic activity was inactivated by incubation with chymotrypsin at pH 8.0.
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PMID:Isolation and activities of the trypsin-modified Vicia angustifolia proteinase inhibitor lacking carboxyl-terminal hexapeptide. 3 67

Purified Japanese monkey pepsinogens I and II contain carbohydrate as a part of the enzyme molecule. By gel filtration on Sephadex G-100, chromatography on DE-32 cellulose, and polyacrylamide disc gel electrophoresis, the carbohydrate moiety could not be separated from the enzyme protein, and the content did not decrease on repeated chromatography. Glycopeptides were obtained by successive digestion of pepsinogens with thermolysin and aminopeptidases and isolated by chromatography on Sephadex G-25 and G-50. Identification and determination of carbohydrate components was performed by paper and gas-liquid chromatographies. The presence of 4 glucosamines, 6 galactoses, 6--8 mannoses, and 8--11 fucoses per molecule of the glycopeptide of both pepsinogens was observed, of which the high content of fucose is especially unique. The molecular weight of the carbohydrate chains should be around 4,000--5,000. The amino acid sequence of a major glycopeptide was deduced to be Ile-Gly-Ile-Gly-Thr-Pro-Gln-Ala-Asn, in which the asparagine residue is the site of attachment of the carbohydrate chain.
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PMID:Monkey pepsinogens and pepsins. III. Carbohydrate moiety of Japanese monkey pepsinogens and the amino acid sequence around the site of its attachment to protein. 10 35

The linkage of corneal keratan sulfate to protein has been investigated. After exhaustive digestion of bovine corneas with papain and pronase, a product was obtained in which aspartic acid was the predominant amino acid and constituted 59% of the total amino acids. A carbohydrate-protein linkage fragment was isolated from this preparation by a relatively simple procedure involving the following steps: (1) partial acid hydrolysis, adsorption of glycopeptides and other cationic material on Dowex 50-X2 (H+) and elution with 0.25 M HCl: (2) paper electrophoresis of the eluted fraction at pH 6.5 and pH 1.9; (3) paper chromatography; and (4) final purification by column chromatography on Aminex A"-5 resin. The structure of the linkage fragment was established as 2-acetamido-1-(L-beta-aspartamido)-1,2-dideoxy-beta-D-glucose (Asn-GlcNAc). Evidence for this structure was obtained from qualitative and quantitative analyses as well as from the migration characteristics in several chromatographic anc electrophoretic systems. Further support for the identity of the isolated compound was provided by treatment with beta-aspartyl N-acetylglucosyl-amine amidohydrolase which specifically cleaves Asn-GlcNAc or asparaginyl-oligosaccharides. It is concluded that corneal keratan sulfate is bound to protein via a N-glycosylamine linkage between N-acetylglucosamine and asparagine: this type of linkage is common to many glycoproteins.
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PMID:The linkage of corneal keratan sulfate to protein. 12 42

1. The oxidation of putrescine in vitro by pig kidney diamine oxidase (EC 1.4.3.6) was increased in the presence of 2-oxosuccinamic acid and malonamic acid. 2. It was inhibited by 3-aminopropionamide, oxaloacetate and pyruvate. 3. 2-Oxosuccinamate was derived from asparagine in virus-transformed baby hamster kidney (BHK) cells growing in tissue culture. 4. Asparagine was decarboxylated more efficiently by transformed than by normal BHK cells. 5. In BHK cells transformed by polyoma virus (Py BHK), 2-oxosuccinamate is the most likely immediate precursor of the 14CO2 arising from [U-14C]asparagine, and there was some evidence for its formation in an asparagine-dependent clone of BHK cells before and after their transformation by hamster sarcoma virus (respectively Asn- and HSV Asn-). 6. The relationship between 2-oxosuccinamate and pyruvate and the possible roles of these two substances in controlling cellular diamine oxidase activity are discussed.
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PMID:Modification of diamine oxidase activity in vitro by metabolites of asparagine and differences in asparagine decarboxylation in normal and virus-transformed baby hamster kidney cells. 18 27

Three analogues of the carboxyl-terminal tricosapeptide of secretin (S5-27), one with glutamine replacing glutamic acid in position 9 (9-Gln-S5-27), a second with asparagine substituted for aspartic acid in position 15 (15-Asn-S5-27), and a third with both replacements (9-Gln-15-Asn-S5-27) were tested for their ability to interact with hormone receptors on dispersed pancreatic acinar cells. Each of these analogues inhibited binding of 125I-labeled vasoactive intestinal peptide (VIP). None of the analogues increased cellular cyclic AMP but each inhibited the increase in cellular cyclic AMP produced by secretin or VIP. At the high affinity VIP receptor (the low affinity secretin receptor) each analogue had an apparent affinity which was greater than that for S5-27, whereas at he low affinity VIP receptor (the high affinity secretin receptor), each of the analogues had an apparent affinity which was the same as that for S5-27. Thus, in S5-27, substituting glutamine in position 9 or asparagine in position 15 makes the fragment more VIP-like but not less secretin-like. These results also provide additional evidence that the receptor having a low affinity for secretin and a high affinity for VIP is functionally distinct from the receptor having a high affinity for secretin and a low affinity for VIP.
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PMID:Interaction of peptides related to secretin with hormone receptors on pancreatic acinar cells. 18 50

One neutral and two acidic glycoasparagines were isolated from the urine of patients with aspartylglycosylaminuria (AGU). The neutral one was identified as beta-Gal-(1 leads to 4)-beta-GlcNAc-Asn. The acidic ones were composed of 1 mole of sialic acid and 2 moles each of galactose and N-acetylglucosamine, attached to asparagine, and were isomeric with respect to the position of sialic acid attachment since they produced the same glycoasparagine on incubation with the neuraminidase [EC 3.2.1.18] from Clostridium perfringens. The structure of the resulting sialic acid-free glycoasparagine was determined to be beta-Gal-beta-GlcNAc-beta-Gal-(1 leads to 4)-beta-GlcNAc-Asn based mainly on the results of sequential enzymatic degradations.
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PMID:Characterization of one neutral and two acidic glycoasparagines isolated from the urine of patients with aspartylglycosylaminuria (AGU). 18 76


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