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 significance of the terminal residues of the red pigment-concentrating hormone (RPCH: Glu-Leu-Asn-Phe-Ser-Pro-Gly-Trp-NH2) for its blanching effect on crustacean chromatophores has been investigated. The chemical synthesis of the following small analogues, starting from the C-terminal amino acid are described: Ac-Trp-NH2, Boc-Gly-Trp-NH2, Ac-Gly-Trp-NH2, Gly-Trp-NH2, Ac-Pro-Gly-Trp-NH2, Glu-Trp-NH2, Glu-Pro-Gly-Trp-NH2, Ac-Pro-Gly and Glu-Pro-Gly-NH2. Assay of the biological activity of the various synthetic compounds in the shrimp Leander adspersus has established that only the C-terminal tryptophan residue is indispensable for the blanching effect of the hormone, although elongation of the chain length improves its potency.
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PMID:Structure-function studies on red pigment-concentrating hormone; the significance of the terminal residues. 68 Jun 42

A series of compounds structurally related to adipokinetic hormone, the decapeptide neurohormone less than Glu-Leu-Asn-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2, have been prepared by synthesis and by enzymic cleavages of synthetic hormone. Their relative agonist activities in mobilising lipids over a fixed time interval (1 h) in locusts were assessed. The similar time courses for lipid release shown by two of the peptide analogues and adipokinetic hormone suggest that the analogues and the hormone are transported to the receptors on the fat body cells, and are also degraded, at similar rates. Consequently, the analogue activities can be correlated with the structural requirements of the locust fat body hormone receptors. The requirements for activity demonstrated in this study are as follows. Residues 1--8 from the N-terminus are necessary to elicit some activity (20%). Residues 5 and 7 in the octapeptide can be changed without affecting activity but L-pyroglutamic acid as the N-terminal residue is necessary formaximum activity both in the octapeptide and the decapeptide. Full activity is achieved only by adding the dipeptide glycyl threonine amide to the active octapeptide 'core'. In the decapeptide, residues cannot be interchanged to the same extent as in the octapeptide without reducing activity. The peptide probably has to be uncharged. Inactive analogues of seven residues or less do not interfere in the hormone-receptor interaction.
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PMID:Structure-activity relationships for the lipid-mobilising action of locust adipokinetic hormone. Synthesis and activity of a series of hormone analogues. 69 7

Protocatechuate 3,4-dioxygenase (EC 1.13.11.3) has been reported to have a molecular weight of 700,000 and to consist of eight identical subunits, each containing one atom of ferric iron and a substrate binding site. This subunit has now been found to dissociate further into four smaller subunits of two nonidentical types (alpha2beta2), upon sodium dodecyl sulfate gel electrophoresis. The molecular weights of the alpha and beta subunits were estimated to be 22,500 and 25,000, respectively. Isoelectric focusing of the enzyme in 6 M urea revealed that the isoelectric points of the alpha and beta subunits were 5.2 and 9.5, respectively. Separation of the two subunits was achieved by chromatography on sulfopropyl (SP)-Sephadex in 6 M urea after treatment of the enzyme with 8 M urea at 37 degrees C for 6 h. The NH2-terminal sequence of the alpha subunit was determined to be Pro-Ile-Glu-Leu-Leu-Pro-Glu-Thr-Pro-Ser-Glx-Thr-Ala-Gly and that of the beta subunit, Pro-Ala-Gln-Asp-Asn-Ala-Arg-Phe-Val-Ile-Arg-Asx-Arg-Asx. Phenylalanine was found as the COOH-terminal residue of the alpha subunit. However, the COOH terminus of the beta subunit was not detected by any of three methods employed.
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PMID:Nonidentical subunits of protocatechuate 3,4-dioxygenase. 82 64

Two derivatives of the C-terminal tripeptide of gastrin devoid of -NH2 from the phenylalanyl residue and of -COOH from the aspartic acid, MBOC-Met.Asn.Phe-OH (I) and MBOC-Met.Asp-OBenz.Phe-OMe (II), stimulated gastric acid secretion in the dog when infused intravenously at doses of 100 to 400 mug/kg-hr. Maximal responses induced by I and II were about 30-40% of that induced by the C-terminal tetrapeptide of gastrin. At a dose of 600 mug/kg-hr, I had an inhibitory action while II initially augmented and then inhibited acid production. Neither the C-terminal amide nor the carboxyl group of the aspartyl residue is essential for the gastric stimulatory activity of gastrin peptides.
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PMID:Dispensability of both the amide of phenylalanine and the carboxyl group of aspartic acid for the stimulation of gastric acid secretion by gastrin peptides in dogs. 83 7

A comparative study is presented of the two phycoerythrins of the unicellular red alga Porphyridium cruentum. Native B-phycoerythrin has a molecular weight of 236,000 +/- 18,000 in 0.05 M potassium phosphate at pH 7.0, and an absorption spectrum with maxima at 545 nm (epsilonM = 2.41 X 10(6) M-1 cm-1) and 563 nm, and a shoulder at 498 nm. The protein carries 38 phycoerythrobilin and at least two phycourobilin prosthetic groups per 240,000 daltons. B-Phycoerythrin is composed of three dissimilar subunits, alpha and beta, each of 17,500 daltons, and gamma of 30,200 daltons. Physical, chemical, and spectroscopic data are consistent with a subunit structure (alphabeta)6gamma for B-phycoerythrin. The alpha and beta subunits carry solely phycoerythrobilin chromophores, while the gamma subunit carries both phycoerythrobilin and phycourobilin groups. The NH2-terminal sequences of the alpha and beta subunits determined by sequential Edman degradation, are shown below: alpha subunit: Met-Lys-Ser-Val-Ile-(Gly-Arg-Phe: beta subunit: Met-Leu-Asp-Ala-Phe-(Thr)-Arg-Val-Val-Val-Asn-Ala-Asx-Ala-( )-Ala-Ala-Tyr-Val. The NH2 terminus of the gamma subunit is blocked. b-Phycoerythrin is polydisperse and exhibits native molecular weights ranging from approximately 40,000 to approximately 260,000, depending on pH, ionic strength, and protein concentration. The absorption spectrum is characterized by maxima at 543 nm (epsilonM = 3.41 X 10(5) M-1 cm-1/35,000 daltons) and 563 nm. The protein carries six phycoerythrobilin groups per 35,000 daltons. b-Phycoerythrin is made up of two dissimilar types of subunits, alpha and beta, of 17,500 daltons each. The alpha and beta subunits derived from b-phycoerythrin appeared equivalent to the corresponding subunits of B-phycoerythrin on the basis of the following criteria: (a) identical chromatographic behavior on Bio-Rex 70 in acid urea; (b) similar amino acid compositions; (c) identical mobilities on polyacrylamide gels in the presence of sodium dodecyl sulfate; (d) similar phycoerythrobilin contents; (e) identical NH2-terminal sequences. These data support, but do not establish unambiguously, the conclusion that b-phycoerythrin may be a component of B-phycoerythrin. The absence or presence, and relative height, of an absorption peak (or shoulder) at 498 nm represents the major difference among the absorption spectra of different classes of phycoerythrins. The present study shows that this spectral feature is dependent on the presence and amount of phycourobilin chromophores in the native protein and is correlated with the presence of the gamma subunit.
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PMID:Subunit structure and chromophore composition of rhodophytan phycoerythrins. Porphyridium cruentum B-phycoerythrin and b-phycoerythrin. 83 25

gamma-Butyrobetaine hydroxylase (4-trimethylaminobutyrate, 2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating), EC 1.14.11.1) has been isolated from Pseudomonas sp AK 1 by ion-exchange, adsorption, and molecular-sieving chromatography. The preparation was homogeneous as judged from electrophoresis in agarose and polyacrylamide gels, isoelectric focusing, and equilibrium sedimentation. The molecular mass was 95 kdaltons as determined by sedimentation equilibrium centrifugation. From electrophoresis in polyacrylamide gel the molecular mass was estimated to 92 kdaltons, from gel filtration through columns of Sephadex G-200 to 86 kdaltons, and from gel filtration through thin layers of Sephadex G-150 and G-200 to 82 kdaltons. Calculation of molecular mass from Stokes radius, sedimentation coefficient, and partial specific volume gave a value of 96 kdaltons, and from the sedimentation coefficient, 93 kdaltons. Gel filtration through Sephadex G-200 in 6 M guanidinium chloride and electrophoresis in polyacrylamide gel containing 3.5 mM sodium dodecyl sulfate resulted in single bands with mobilities corresponding to molecular masses of 39 and 37 kdaltons, respectively, indicating that the enzyme is composed of two polypeptides chains with similar size. NH2-terminal amino acid sequencing in three cycles resulted in two amino acids in each cycle (Ala + Asn, Ala + Ile, Ala + Ile). The Stokes radius was 3.8 nm, corresponding to a diffusion coefficient of 5.7 X 10(-7) cm2/s. A sedimentation coefficient of 5.8 X 10(-13) s and a frictional ratio of 1.26 was found. The partial specific volume was 0.729 mL/g at 20 degrees C as calculated from amino acid analysis. The isoelectric point was 5.1, as determined by isoelectric focusing analysis. The light absorption in the ultraviolet and visible regions was that of a protein without light-absorbing prosthetic groups. The absorption coefficient at 280 nm of a 1.0% solution at pH 6.5 was 12.6. Amino acid analysis by ion-exchange chromatography showed a half-cystine content of 19 mol per 95 kg of protein (23 residues/1000). Thirteen sulfhydryl groups were found by colorimetric analysis before as well as after reduction with NaBH4, indicating absence of disulfide bonds. Less than 0.1 mol of iron was found per mol of enzyme.
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PMID:Purification and properties of gamma-butyrobetaine hydroxylase from Pseudomonas sp AK 1. 86 Dec 3

A seed protein with an apparent molecular weight of 5000 has been isolated and purified from Ricinus communis. This protein has a very high content of glutamine and an unusual ultraviolet absorption spectrum. The amino-terminal sequence of 22 residues determined by automatic Edman degradation is: NH2-Pro-Ser-Gln-Gln-Gly-Cys-Cys-Gly-Gln-Ile-Gln-Glu-Gln-Gln-Asn-Leu-Arg-Gln-Cys-Gln-Glu-Tyr-.
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PMID:Isolation and characterization of a low-molecular weight seed protein from Ricinus communis. 88 36

The complete amino acid sequence of the beta chain of cholera enterotoxin was determined: NH2-Thr-Pro-Gln-Asn-Ile-Thr-Asp-Leu-Cys-Ala-Glu-Tyr-His-Asn-Thr-Gln-Ile-His-Thr-Leu-Asn-Asn-Lys-Ile-Phe-Ser-Tyr-Thr-Glu-Ser-Leu-Ala-Gly-Lys-Arg-Glu-Met-Ala-Ile-Ile-Thr-Phe-Lys-Asn-Gly-Ala-Thr-Phe-Gln-Val-Glu-Val-Pro-Gly-Ser-Gln-His-Ile-Asp-Ser-Gln-Lys-Lys-Ala-Ile-Glu-Arg-Met-Lys-Asn-Thr-Leu-Arg-Ile-Ala-Tyr-Leu-Thr-Glu-Ala-Lys-Val-Glu-Lys-Leu-Cys-Val-Trp-Asn-Asn-Lys-Thr-Pro-His-Ala-Ile-Ala-Ala-Ile-Ser-Met- Ala-Asn-COOH. The sequence was obtained from automated sequence analysis of intact beta chain, cyanogen bromide fragments, and a fragment generated by cleavage at a single tryptophan with 2-(2-nitrophenylsulfenyl)-3-methyl-3-bromoindolenine as well as from manual sequence analysis of tryptic peptides using 5-dimethylaminonaphthalene-1-sulfonyl-monitored Edman methodology. The tryptic peptides accounted for all 103 residues established for the complete primary structure.
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PMID:Covalent structure of the beta chain of cholera enterotoxin. 90 63

Two heterodetic cyclic nonapeptides, X-Cys-Thr-Lys-Ser-Asn-Pro-Pro-Gln-Cys-Y (Ia: X = Ac, Y = NH2; Ib: X = H, Y = OH), which correspond to residues 14-22 in the sequence of Bowman-Birk inhibitor, have been synthesized by Merrifield's solid-phase method. Inhibitory activities of Ia and Ib on tryptic hydrolysis of amide and ester substrates were examined. When Gly2-Lys-Gly3 and Tos-Arg-OMe were used as substrates, the values of I50 for the peptide Ia were calculated to be 3.6 micron and 40 micron, respectively. When Gly2-Lys-Gly3 was used as a substrate, the value of Ki was calculated to be 1.5 micron. Ia was hydrolyzed slowly by trypsin, losing the inhibitory activity. When the Lys-Ser bond of Ia was cleved with trypsin, the modified Ia could not be regenerated by trypsin. The linear peptide S, S'-dicarboxamidomethyl-Ia also was inactive and appeared to be a good substrate. Optical rotatory dispersion studies showed that the active fragments have characteristic conformations which were lost upon modification to inactive derivatives.
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PMID:Studies on the synthesis of proteinase inhibitors. I. Synthesis and activity of nonapeptide fragments of soybean Bowman-Birk inhibitor. 91 12

The structure of a light-adapting hormone of the shrimp, Pandalus borealis, has been determined. The hormone, which had been isolated from Pandalus eyestalks and which adapts the shrimp to brighter light conditions by causing the pigment in the distal retinal pigment cells of the eye to move into a more proximal position, is the peptide: Asn-Ser-Gly-Met-Ile-Asn-Ser-Ile-Leu-Gly-Ile-Pro-Arg-Val-Met-Thr-Glu-Ala-NH2. The structure was obtained by sequence analysis by the dansyl-Edman method of the intact hormone and of isolated tryptic and thermolytic peptides.
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PMID:Structure of a light-adapting hormone from the shrimp, Pandalus borealis. 95 51


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