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.

ZnII Complex with a Phenanthroline-Containing Macrocycle as Receptor for Amino Acids and Dipeptides − Hydrolysis of an Activated Peptide Bond

2003 ◽  
Vol 2003 (10) ◽  
pp. 1974-1983 ◽  
Author(s):  
Carla Bazzicalupi ◽  
Andrea Bencini ◽  
Emanuela Berni ◽  
Antonio Bianchi ◽  
Patrizia Fornasari ◽  
...  
Keyword(s):  
Amino Acids ◽  
Peptide Bond ◽  
Hydrolysis Of

THE ACTION OF ANHYDROUS ACIDS ON ATP:CREATINE PHOSPHOTRANSFERASE

1962 ◽  
Vol 40 (5) ◽  
pp. 1018-1022 ◽  
Author(s):  
Florante A. Quiocho ◽  
Felix Friedberg
Keyword(s):  
Amino Acids ◽  
Phosphoric Acid ◽  
Formic Acid ◽  
Sulphuric Acid ◽  
Acyl Migration ◽  
Peptide Bonds ◽  
Hydrolysis Of ◽  
Anhydrous Formic Acid

Treatment of ATP:creatine phosphotransferase with anhydrous sulphuric acid permits transposition of 24% of the threonine residues and 69% of the serine residues. Treatment with anhydrous phosphoric acid yields similar results: 41% of the threonine residues and 60% of the serine residues are rearranged. Anhydrous formic acid does not induce an N- to O-acyl migration in the protein.Non-specific hydrolysis of peptide bonds or destruction of certain amino acids that might have occurred simultaneously with rearrangement during the anhydrous sulphuric or anhydrous phosphoric acid appears to be very slight. When the protein is treated with anhydrous sulphuric acid, however, phenylalanine "disappears" almost completely from the chromatogram.

scholarly journals Recognition of protein-linked glycans as a determinant of peptidase activity

2017 ◽  
Vol 114 (5) ◽  
pp. E679-E688 ◽  
Author(s):  
Ilit Noach ◽  
Elizabeth Ficko-Blean ◽  
Benjamin Pluvinage ◽  
Christopher Stuart ◽  
Meredith L. Jenkins ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Peptide Bond ◽  
Peptidase Activity ◽  
Peptide Bonds ◽  
Crystallographic Structures ◽  
Covalently Linked ◽  
Biochemical Analyses ◽  
Life On Earth ◽  
Glycoprotein Degradation ◽  
Hydrolysis Of

The vast majority of proteins are posttranslationally altered, with the addition of covalently linked sugars (glycosylation) being one of the most abundant modifications. However, despite the hydrolysis of protein peptide bonds by peptidases being a process essential to all life on Earth, the fundamental details of how peptidases accommodate posttranslational modifications, including glycosylation, has not been addressed. Through biochemical analyses and X-ray crystallographic structures we show that to hydrolyze their substrates, three structurally related metallopeptidases require the specific recognition of O-linked glycan modifications via carbohydrate-specific subsites immediately adjacent to their peptidase catalytic machinery. The three peptidases showed selectivity for different glycans, revealing protein-specific adaptations to particular glycan modifications, yet always cleaved the peptide bond immediately preceding the glycosylated residue. This insight builds upon the paradigm of how peptidases recognize substrates and provides a molecular understanding of glycoprotein degradation.

scholarly journals Hydrolysis of the Peptide Bond and Amino Acid Modification with Hydriodic Acid

1971 ◽  
Vol 24 (4) ◽  
pp. 1235 ◽  
Author(s):  
AS Inglis ◽  
PW Nicholls ◽  
CM Roxburgh
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Boiling Point ◽  
Amino Acid Analysis ◽  
Peptide Bond ◽  
Hydriodic Acid ◽  
Acid Modification ◽  
Amino Acid Modification ◽  
Hydrolysis Of

Reaction of hydriodic acid with peptides and proteins has been studied. At the boiling point, hydrolysis of the peptide bond, particularly stable bonds linking valine and isoleucine residues, is facile. Several amino acids react with constantboiling hydriodic acid but the only reactions detrimental to the amino acid analysis are the reduction of serine with concomitant formation of alanine, and the destruction of tryptophan. Gentler conditions of hydrolysis with diluted hydriodic acid are required for analysis of serine. Good results for analysis of proteins for amino acids may be obtained after a 6-hr hydrolysis period.

scholarly journals Unwanted hydrolysis or α/β-peptide bond formation: how long should the rate-limiting coupling step take?

RSC Advances ◽  
2019 ◽  
Vol 9 (53) ◽  
pp. 30720-30728 ◽  
Author(s):  
Viktória Goldschmidt Gőz ◽  
Adrienn Nagy ◽  
Viktor Farkas ◽  
Ernő Keszei ◽  
András Perczel
Keyword(s):  
Amino Acids ◽  
Bond Formation ◽  
Side Reaction ◽  
Peptide Bond ◽  
Amide Bond ◽  
Peptide Bond Formation ◽  
Active Esters ◽  
Amide Bond Formation ◽  
Rate Limiting ◽  
Hydrolysis Of

Parallel to the amide bond formation, the hydrolysis of the active esters of α/β-amino acids, as an unwanted side reaction limiting coupling efficacy, is studied.

Chemical changes in ultra-heat-treated milk during storage: I. Hydrolysis of casein by incubation with pronase and a peptidase mixture

1977 ◽  
Vol 44 (2) ◽  
pp. 259-266 ◽  
Author(s):  
A. B. Möller ◽  
A. T. Andrews ◽  
G. C. Cheeseman
Keyword(s):  
Amino Acids ◽  
Maillard Reaction ◽  
Microsomal Fraction ◽  
Streptomyces Griseus ◽  
Milk Proteins ◽  
Chemical Changes ◽  
Peptide Bonds ◽  
Uht Milk ◽  
Heat Treated ◽  
Hydrolysis Of

SummaryCasein samples from untreated milk and stored ultra-heat-treated (UHT) milk were hydrolysed with pronase (protease ex Streptomyces griseus K-1) and subsequently with a mixture of peptidases prepared from the microsomal fraction of hog kidneys. Incubation of casein from unheated milk with pronase alone hydrolysed 70–80% of peptide bonds involving Ile, Leu, Tyr, Phe and His residues; other amino acids were released less well and proline hardly at all. The pronase/peptidase treatment resulted in 90–100% hydrolysis of peptide bonds involving all amino acids, including proline.Caseins from stored UHT milks were more resistant to proteolysis than casein from unheated milk. Reduced release of all amino acids was observed from samples taken after storage at 37 °C for 12 months or longer and for Lys, Arg and Asn residues from samples taken after storage at 30 °C for 14 months. Resistance to proteolysis was attributed to the Maillard reaction between milk proteins and lactose during storage of UHT milk.

Scandium(iii) triflate-promoted serine/threonine-selective peptide bond cleavage

2017 ◽  
Vol 53 (23) ◽  
pp. 3311-3314 ◽  
Author(s):  
Jizhi Ni ◽  
Youhei Sohma ◽  
Motomu Kanai
Keyword(s):  
Bond Cleavage ◽  
Peptide Bond ◽  
High Conversion ◽  
Selective Hydrolysis ◽  
Conversion Yield ◽  
Peptide Bonds ◽  
Peptide Bond Cleavage ◽  
High Conversion Yield ◽  
Site Selective ◽  
Hydrolysis Of

The site-selective hydrolysis of peptide bonds at Ser and Thr positions was promoted by scandium(iii) triflate with a high conversion yield.

Synthesis of phosphonylmethyl analogues of diribonucleoside monophosphates containing modified internucleotide bond

1987 ◽  
Vol 52 (10) ◽  
pp. 2572-2588 ◽  
Author(s):  
Ivan Rosenberg ◽  
Antonín Holý
Keyword(s):  
Methyl Esters ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Oligonucleotide Synthesis ◽  
Amino Groups ◽  
Methyl Group ◽  
Hydrolysis Of ◽  
Derivatives Of ◽  
Methylene Group ◽  
Phosphotriester Method

Two types of (2'-5')- and (3'-5')-isomers of analogues of diribonucleoside monophosphates derived from O-phosphonylmethyl derivatives of ribonucleosides, differing in the position of the methylene group in the internucleotide bond (type A, B, C, and D) have been synthesized. The compounds were prepared from methyl esters of O-phosphonylmethylribonucleosides I and XVII by a procedure analogous to the phosphotriester method of oligonucleotide synthesis. The phosphonate moiety was protected with the methyl group. After protection of the hydroxyl or amino groups, the compounds I or XVII were condensed with protected ribonucleosides VIII, XI, XIV, XXIII to afford the neutral diesters IX, XII, XV, XXIV, XXVI, and XXVIII which were isolated by short column chromatography on silica gel. Deprotection, ion-exchange chromatography, and semipreparative HPLC gave (2'-5')- and (3'-5')-isomers of both types of O-phosphonylmethyl analogues of diribonucleoside monophosphates (X, XIII and XXV, XXVII). All these compounds are resistant towards cleavage with ribonucleases A and T2 and with snake venom exonuclease. Under conditions of alkaline hydrolysis of RNA, the analogues of the type A and B are completely stable whereas compounds of the type C and D are degraded to form 2'- or 3'-O-phosphonylmethylribonucleosides and 3'-terminal ribonucleosides.

Post-proline endopeptidase. Partial purification and characterization of the enzyme from pig kidneys

1982 ◽  
Vol 47 (4) ◽  
pp. 1139-1148 ◽  
Author(s):  
Karel Hauzer ◽  
Linda Servítová ◽  
Tomislav Barth ◽  
Karel Jošt
Keyword(s):  
Specific Activity ◽  
Gel Filtration ◽  
Peptide Bond ◽  
Exchange Chromatography ◽  
Partial Purification ◽  
Purification And Characterization ◽  
Optimum Ph ◽  
Hydrolysis Of ◽  
Prolyl Leucyl Glycinamide

Post-proline endopeptidase was isolated from pig kidneys and partially purified. The procedure consisted of fractionation with ammonium sulphate, ion exchange chromatography on DEAE-Sephadex A-50, gel filtration on Sephadex G-200 and rechromatography on DEAE-Sephadex A-50. The preparation had 55 times higher specific activity than the crude extract and did not contain any contaminating enzymic activities. The enzyme cleaved a number of proline-containing peptides and was strictly specific in catalyzing the hydrolysis of the peptide bond on the carboxyl side of the proline residue. The optimum pH for the hydrolysis of the synthetic peptides benzyl-oxycarbonylglycyl-prolyl-leucyl-glycinamide and benzyloxycarbonyl-glycyl-proline β-naphtylamide was 7.8-8.0 and, in the case of benzyloxycarbonylglycyl-proline p-nitroanilide, 7.2 to 7.5. For the hydrolysis of the tetrapeptide benzyloxycarbonylglycyl-prolyl-leucyl-glycinamide, the Km value of 75 μ mol l-1 was obtained.

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