Formation and instability of o-phthalaldehyde derivatives of amino acids

Garcı́a-Alvarez-Coque, M.C.; Medina-Hernández, M.J.; Camañas, R. M. Villanueva; Fernández, Carmen

doi:10.1016/0003-2697(89)90346-1

Cited by 153 publications

(56 citation statements)

References 46 publications

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“…In the literature, there have been reported many spetrophotometric methods for the determination of NAC. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] One group of described methods involves redox reactions with NAC in which a colored compound is formed or decomposed during determination. Among the described indirect spectrophotometric procedures one of the most common approaches to the determination of NAC is based on the coupled redox complexation reaction.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Spectrophotometric Determination of N-Acetyl-L-cysteine Ethyl Ester (NACET) Generating Chromogenic Copper(I)Ln Complexes with Different Ligands

Kukoc-Modun¹,

Tsikas²,

Kraljević³

et al. 2017

Croat. Chem. Acta

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Three simple, sensitive and robust kinetic spectrophotometric methods for the determination of a novel lipophilic thiol compound, N-acetyl-L-cysteine ethyl ester (NACET), have been developed and validated. The methods are based on the reduction of Cu(II)-ligand complex to Cu(I)-ligand complex with the analyte. Studied ligands were neocuproine, bicinchoninic acid (BCA) and bathocuproine disulfonic acid (BCS). The development of chromogenic complexes was followed using kinetic setup with spectrophotometric detection at 458, 562 and 483 nm for the reactions of NACET with neocuproine, BCA and BCS, respectively. The calculated reaction orders with respect to NACET concentration were found to be 1.07, 1.01, 1.07, respectively, thus confirming a first order of reaction. The initial rate and fixed time methods were utilized for constructing calibration curves. Assays limits of detection were 1.4 × 10 -7 , 3.2 × 10 −7 and 6.0 × 10 −8 mol L -1 , respectively. The analytical performance of the methods, in terms of accuracy and precision, was established.

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Section: Introductionmentioning

confidence: 99%

Kinetic Spectrophotometric Determination of N-Acetyl-L-cysteine Ethyl Ester (NACET) Generating Chromogenic Copper(I)Ln Complexes with Different Ligands

Kukoc-Modun¹,

Tsikas²,

Kraljević³

et al. 2017

Croat. Chem. Acta

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“…However, these isoindole derivatives are unstable. [9] Previous studies have demonstrated that the formation of OPA derived fluorescent amino compounds are more stable in the presence of the thiol 3-mercaptopropionic acid (MPA) instead of the more commonly used 2-mercaptoethanol. [10][11][12] In this manuscript we describe a simple and rapid automatic online precolumn derivatization HPLC method for the quantitation of plasma amino acids.…”

Section: Introductionmentioning

confidence: 99%

Simple and rapid quantitative high-performance liquid chromatographic analysis of plasma amino acids

Frank

Powers

2007

Journal of Chromatography B

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A simple and rapid high performance liquid chromatographic method for the determination of plasma amino acids was developed. The method uses minimal sample volume and automated online precolumn derivitization of amino acids with o-phthalaldehyde and fluorescent detection. Amino acids are separated by a simplified gradient without column heating. The assay is linear from 5 to 1000μmol/L for all amino acids. Recovery of amino acids was between 91 and 108%, intra-assay coefficient of variation (CV) was 1-7%, and inter-assay CV was 2-12%. The simple sample preparation and minimal sample volume make the method useful for the quantitation of amino acids in both patient and experimental animal samples.

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“…Approximately 100 pl 6 M HCl/O.l% phenol solution was placed in the bottom of the vial and the samples were hydrolysed under reduced pressure (approximately 133 Pa) for 18 h at 11O'C. Amino acid analyses were performed using pre-column derivatization with ophthaldialdehyde (Merck Schuchart, FRG'I using an autosampler (LKB 21 57) [6]. C-terminal prolinamide was analyzed by the phenylisothiocarbamoyl method [7].…”

Section: Amino Acid and Carbohydrate Analjvismentioning

confidence: 99%

Determination of the covalent structure of an N‐ and C‐terminally blocked glycoprotein from endocuticle of Locusta migratoria

Talbo¹,

Højrup²,

Rahbek-Nielsen³

et al. 1991

European Journal of Biochemistry

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The complete structure of a protein isolated from endocuticle of sexually mature locusts, Locusta migratoria, has been determined by a combination of automatic Edman degradation and plasma desorption mass spectrometry. The protein is extensively post-translationally modified. The N-terminal is 5-oxoproline (pyroglutamic acid) and the C-terminal proline residue is amidated. Furthermore, the protein is glycosylated by a single N-acetylgalactosamine residue at one, two or three threonines. The N-terminal sequence was obtained by analysing the N-acetylated N,O-permethylated derivative using plasma desorption mass spectrometry. The position and type of carbohydrate were determined by combining an HPLC-based carbohydrate analysis with the peak pattern of the phenylthiohydantoin derivative in automatic sequencing and with mass information on peptides.The protein has pronounced similarity to cuticular proteins from larvae of diptera and lepidoptera, but only slight resemblance to the previously sequenced locust exocuticular proteins. This indicates a similarity between soft larval cuticles and locust endocuticle, a similarity which may extend to their mechanical properties.Locust cuticle consists of a relatively soft endocuticle, which contains mainly acidic proteins, and a harder exocuticle, containing more basic proteins [l]. The proteins in the exocuticle of the migratory locust Locusta migratoria can only be extracted immediately after ecdysis, before cuticular sclerotization is initiated. Several of the exocuticular proteins have been purified and a few have been sequenced using a combination of "' Cf plasma desorption mass spectrometry and Edman degradation [2, 31. The extractable, endocuticular proteins from mature locust abdominal cuticle have been characterised using gel electrophoresis and amino acid analysis [l]. The proteins resemble the exocuticular proteins in the lack of sulphur-containing amino acids and a relatively high content of proline. The main differences are low isoelectric points (PI 4 -6) and high contents of hydrophilic amino acids in endocuticular proteins.The presence of glycosylated proteins in soft larval lepidopteran cuticle has been described [4], but the specific glycosylation sites and the detailed structures of the glycosyl residues have not been reported. We have now determined the complete structure of a glycosylated endocuticular protein, Correspondence to P.

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Formation and instability of o-phthalaldehyde derivatives of amino acids

Cited by 153 publications

References 46 publications

Kinetic Spectrophotometric Determination of N-Acetyl-L-cysteine Ethyl Ester (NACET) Generating Chromogenic Copper(I)Ln Complexes with Different Ligands

Kinetic Spectrophotometric Determination of N-Acetyl-L-cysteine Ethyl Ester (NACET) Generating Chromogenic Copper(I)Ln Complexes with Different Ligands

Simple and rapid quantitative high-performance liquid chromatographic analysis of plasma amino acids

Determination of the covalent structure of an N‐ and C‐terminally blocked glycoprotein from endocuticle of Locusta migratoria

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