The reaction of cystine and Alanine-3-sulphinic acid with halogens

1973 ◽  
Vol 26 (8) ◽  
pp. 1771 ◽  
Author(s):  
PG Gordon
Keyword(s):  
Amino Acids ◽  
Carboxylic Acid ◽  
Peptide Bond ◽  
Cysteic Acid ◽  
Mixed Anhydride ◽  
Mechanism Of Formation

Aqueous chlorine and bromine react with cystine, cysteine, alanine-3- sulphinic acid, and cystine S,S-dioxide to give cysteic acid (3) and cysteicylcysteic acid (2).' When the reaction is performed in the presence of other amino acids it is possible to obtain mixed peptides. The mechanism of formation of the peptide bond is discussed and a sulphonic-carboxylic acid mixed anhydride is proposed as an intermediate.

scholarly journals pH-Dependent peptide bond formation by the selective coupling of α-amino acids in water

2021 ◽  
Vol 57 (1) ◽  
pp. 73-76
Author(s):  
Long-Fei Wu ◽  
Ziwei Liu ◽  
John D. Sutherland
Keyword(s):  
Amino Acids ◽  
Bond Formation ◽  
Peptide Bond ◽  
Peptide Bond Formation ◽  
Mixed Anhydride ◽  
Ph Dependent ◽  
Peptide Elongation

Selective peptide elongation chemistry by coupling α-amino acids via mixed anhydride intermediates in water.

The Kinetics of Inhibition of the Action of Thrombin by the Fibrinopeptides Formed during the Clotting of Fibrinogen

1966 ◽  
Vol 16 (01/02) ◽  
pp. 277-295 ◽  
Author(s):  
A Silver ◽  
M Murray
Keyword(s):  
Amino Acids ◽  
Competitive Inhibition ◽  
Amorphous Material ◽  
Peptide Bond ◽  
Initial Reaction ◽  
Reaction Products ◽  
Coagulation Mechanism ◽  
Kinetics Of ◽  
Kinetics Of Inhibition ◽  
Burk Plot

SummaryVarious investigators have separated the coagulation products formed when fibrinogen is clotted with thrombin and identified fibrinopeptides A and B. Two other peaks are observed in the chromatogram of the products of coagulation, but these have mostly been dismissed by other workers. They have been identified by us as amino acids, smaller peptides and amorphous material (37). We have re-chromatographed these peaks and identified several amino acids. In a closed system of fibrinogen and thrombin, the only reaction products should be fibrin and peptide A and peptide B. This reasoning has come about because thrombin has been reported to be specific for the glycyl-arginyl peptide bond. It is suggested that thrombin also breaks other peptide linkages and the Peptide A and Peptide B are attacked by thrombin to yield proteolytic products. Thrombin is therefore probably not specific for the glycyl-arginyl bond but will react on other linkages as well.If the aforementioned is correct then the fibrinopeptides A and B would cause an inhibition with the coagulation mechanism itself. We have shown that an inhibition does occur. We suggest that there is an autoinhibition to the clotting mechanism that might be a control mechanism in the human body.The experiment was designed for coagulation to occur under controlled conditions of temperature and time. Purified reactants were used. We assembled an apparatus to record visually the speed of the initial reaction, the rate of the reaction, and the density of the final clot formed after a specific time.The figures we derived made available to us data whereby we could calculate and plot the information to show the mechanism and suggest that such an inhibition does exist and also further suggest that it might be competitive.In order to prove true competitive inhibition it is necessary to fulfill the criteria of the Lineweaver-Burk plot. This has been done. We have also satisfied other criteria of Dixon (29) and Bergman (31) that suggest true competitive inhibition.

Synthesis of Linear Steroid Oligoesters Based on Etienic Acid

2002 ◽  
Vol 67 (11) ◽  
pp. 1709-1718 ◽  
Author(s):  
Miroslav Reschel ◽  
Miloš Buděšínský ◽  
Ivan Černý ◽  
Vladimír Pouzar ◽  
Pavel Drašar
Keyword(s):  
Carboxylic Acid ◽  
Nmr Spectra ◽  
Mixed Anhydride

Linear oligoesters based on etienic acid (3β-hydroxyandrost-5-ene-17β-carboxylic acid) containing 2-4 steroid units were prepared employing mixed anhydride esterification. NMR spectra of the oligomeric steroids have been fully assigned.

Synthesis and Antibacterial Potency of 4-Methyl-2,7-dioxo-1,2,3,4,7,10- hexahydropyrido[2,3-ƒ]quinoxaline-8-carboxylic acid, Selected [a]-Fused Heterocyles and Acyclic Precursors

2007 ◽  
Vol 62 (11) ◽  
pp. 1453-1458 ◽  
Author(s):  
Yusuf M. Al-Hiari ◽  
Ali M. Qaisia ◽  
Mohammad Y.Abu Shuheil ◽  
Mustafa M. El-Abadelah ◽  
Wolfgang Voelter
Keyword(s):  
Amino Acids ◽  
Carboxylic Acid ◽  
Antibacterial Activities ◽  
Sodium Dithionite ◽  
E Coli ◽  
Pipecolinic Acid

The reaction of 7-chloro-1-cyclopropyl-6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (7) with each of sarcosine and (±)-pipecolinic acid afforded the corresponding N-(4- oxoquinolin-7-yl)-α-amino acids 8 and 9. Reductive lactamization of the latter with sodium dithionite gave hexahydropyrido[2,3- f ]quinoxaline (10) and octahydrodipyrido[1,2-a : 2,3- f ]quinoxaline (11) derivatives, respectively. Compounds 8 - 11 and their homologs 1 - 6, accessible from (S)-proline, (2S, 4R)-4-hydroxyproline and (S)-tetrahydroisoquinoline-3-carboxylic acid exhibit good to excellent antibacterial activities against E. coli and S. aureus.

scholarly journals Amino acid production in isolated rat liver mitochondria

1973 ◽  
Vol 134 (2) ◽  
pp. 431-436 ◽  
Author(s):  
W. Ferdinand ◽  
W. Bartley ◽  
V. Broomhead
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Lipid Hydroperoxide ◽  
Liver Mitochondria ◽  
Cysteic Acid ◽  
Rat Liver Mitochondria ◽  
Isolated Mitochondria ◽  
Selective Retention

Amino acid analyses of mitochondrial membranes are compared with the amino acid composition of whole mitochondria (Alberti, 1964) and found to be very similar except in the cystine content. The composition of the endogenous amino acids found in freshly prepared mitochondria has been established and shown to differ considerably from the amino acid composition of membranes or whole mitochondria. The amino acids produced during anaerobic incubation of mitochondria at pH7.4, on the other hand, resemble the membrane in composition, supporting the view that neutral proteinase activity is responsible for their appearance. Aerobic incubation produces a similar pattern of amino acids except that amino acids such as proline, serine, asparagine, glutamic acid and glutamine, which can be metabolically utilized under aerobic conditions, are present to a smaller extent. The presence of large relative concentrations of endogenous taurine, cysteic acid and oxidized glutathione and the accumulation of taurine during incubation is found. The selective retention of taurine and cysteic acid within the mitochondria is established. It is proposed that the first step in the degeneration of isolated mitochondria results from lipid hydroperoxide accumulation caused by the lack of glutathione reductase in isolated mitochondria.

Enzymatic resolution of (±)-5-phenyl-4,5-dihydroisoxazole-3-carboxylic acid ethyl ester and its transformations into polyfunctionalised amino acids and dipeptides

2009 ◽  
Vol 20 (16) ◽  
pp. 1940-1947 ◽  
Author(s):  
Giuseppe Cremonesi ◽  
Piero Dalla Croce ◽  
Alessandra Forni ◽  
Maddalena Gallanti ◽  
Raffaella Gandolfi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Carboxylic Acid ◽  
Ethyl Ester ◽  
Acid Ethyl Ester ◽  
Enzymatic Resolution

scholarly journals Isolation, purification and structure of exochelin MS, the extracellular siderophore from Mycobacterium smegmatis

1995 ◽  
Vol 305 (1) ◽  
pp. 187-196 ◽  
Author(s):  
G J Sharman ◽  
D H Williams ◽  
D F Ewing ◽  
C Ratledge
Keyword(s):  
Amino Acids ◽  
Mycobacterium Smegmatis ◽  
Methyl Esters ◽  
Three Dimensional ◽  
Iron Chelation ◽  
Peptide Bond ◽  
Exchange Chromatography ◽  
Peptide Bonds ◽  
Hydrolysis Of ◽  
Gallium Complex

The extracellular siderophore from Mycobacterium smegmatis, exochelin MS, was isolated from iron-deficiently grown cultures and purified to > 98% by a combination of ion-exchange chromatography and h.p.l.c. The material is unextractable into organic solvents, is basic (pI = 9.3-9.5), has a lambda max at 420 nm and a probable Ks for Fe3+ of between 10(25) and 10(30). Its structure has been determined by examination of desferri- and ferri-exochelin and its gallium complex. The methods used were electrospray-m.s. and one- and two-dimensional (NOESY, DQF-COSY and TOCSY) 1H n.m.r. The constituent amino acids were examined by chiral g.l.c analysis of N-trifluoroacetyl isopropyl and N-pentafluoropropionyl methyl esters after hydrolysis, and reductive HI hydrolysis, of the siderophore. The exochelin is a formylated pentapeptide: N-(delta-N-formyl,delta N-hydroxy-R-ornithyl) -beta-alaninyl-delta N-hydroxy-R-ornithinyl-R-allo-threoninyl-delta N-hydroxy-S-ornithine. The linkages involving the three ornithine residues are via their delta N(OH) and alpha-CO groups leaving three free alpha-NH2 groups. Although there are two peptide bonds, these involve the three R (D)-amino acids. Thus the molecule has no conventional peptide bond, and this suggests that it will be resistant to peptidase hydrolysis. The co-ordination centre with Fe3+ is hexadenate in an octahedral structure involving the three hydroxamic acid groups. Molecular modelling shows it to have similar features to other ferric trihydroxamate siderophores whose three-dimensional structures have been established. The molecule is shown to have little flexibility around the iron chelation centre, although the terminal (Orn-3) residue, which is not involved in iron binding except at its delta N atom, has more motional freedom.

scholarly journals The rate-limiting step of protein synthesis in vivo and in vitro and the distribution of growing peptides between the puromycinlabile and puromycin-non-labile sites on polyribosomes

1971 ◽  
Vol 122 (3) ◽  
pp. 267-276 ◽  
Author(s):  
D. C. N. Earl ◽  
Susan T. Hindley
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Donor Site ◽  
Peptide Bond ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Donor And Acceptor ◽  
Rate Limiting

1. At 3 min after an intravenous injection of radioactive amino acids into the rat, the bulk of radioactivity associated with liver polyribosomes can be interpreted as growing peptides. 2. In an attempt to identify the rate-limiting step of protein synthesis in vivo and in vitro, use was made of the action of puromycin at 0°C, in releasing growing peptides only from the donor site, to study the distribution of growing peptides between the donor and acceptor sites. 3. Evidence is presented that all growing peptides in a population of liver polyribosomes labelled in vivo are similarly distributed between the donor and acceptor sites, and that the proportion released by puromycin is not an artifact of methodology. 4. The proportion released by puromycin is about 50% for both liver and muscle polyribosomes labelled in vivo, suggesting that neither the availability nor binding of aminoacyl-tRNA nor peptide bond synthesis nor translocation can limit the rate of protein synthesis in vivo. Attempts to alter this by starvation, hypophysectomy, growth hormone, alloxan, insulin and partial hepatectomy were unsuccessful. 5. Growing peptides on liver polyribosomes labelled in a cell-free system in vitro or by incubating hemidiaphragms in vitro were largely in the donor site, suggesting that either the availability or binding of aminoacyl-tRNA, or peptide bond synthesis, must be rate limiting in vitro and that the rate-limiting step differs from that in vivo. 6. Neither in vivo nor in the hemidiaphragm system in vitro was a correlation found between the proportion of growing peptides in the donor site and changes in the rate of incorporation of radioactivity into protein. This could indicate that the intracellular concentration of amino acids or aminoacyl-tRNA limits the rate of protein synthesis and that the increased incorporation results from a rise to a higher but still suboptimum concentration.

A Fundamental Study of Quantitative Desulfurization of Sulfur Containing Amino Acids by Raney Nickel and its Character

1981 ◽  
Vol 36 (3) ◽  
pp. 370-374 ◽  
Author(s):  
Shinji Ohmori ◽  
Kazuko Takahashi ◽  
Mikiko Ikeda ◽  
Toshihiko Ubuka
Keyword(s):  
Amino Acids ◽  
Raney Nickel ◽  
Hydrogen Gas ◽  
Cysteic Acid ◽  
Sulfinic Acid ◽  
Fundamental Study ◽  
Homocysteic Acid ◽  
Ni Alloy ◽  
Ph Range ◽  
Sulfur Containing

Abstract The desulfurization of several naturally occurring sulfur-containing amino acids by Raney nickel was studied under various conditions. Raney nickel, which was prepared by treating Al-Ni alloy with 5 N NaOH at 60 °C for 30 min, and was not washed with water, was most active and desulfurized, in quantitative yield, methionine, homocysteine, homocystine, homocysteine sulfinic acid, S-(2-carboxy-n-propyl)-L-cysteine, cysteine, cystine, cysteine sulfinic acid and S-methylcysteine sulfoxide. Raney nickel prepared from 100 mg of Al-Ni alloy desulfurized quantitatively up to 40 μmol methionine at 60 °C for 30 min. The desulfurization occurred effectively in the pH range of 7 and 13, but not below 7. Methionine sulfone, cysteic acid, and homocysteic acid were not subject to the reaction. The Raney nickel was deactivated by H2S, and H2O2, or combustion. Desulfurization activity was not enhanced by hydrogen gas.

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