Amino add analysis

The amino add analysis of all peptide chains on the resins indicated a ratio of Pro Val 6.6 6.0 (calcd. 6 6). The peptides were then cleaved from the resin with 30% HBr in acetic acid and chromatogra phed on sephadex LH-20 in 0.001 M HCl. 335 mg dodecapeptide was isolated. Hydrolysis followed by quantitative amino acid analysis gave a ratio of Pro Val - 6.0 5.6 (calcd. 6 6). Cycll2ation in DMF with Woodward s reagent K (see scheme below) yielded after purification 138 mg of needles of the desired cyc-lododecapeptide with one equiv of acetic add. The compound yielded a yellow adduct with potassium picrate, and here an analytically more acceptable ratio Pro Val of 1.03 1.00 (calcd. 1 1) was found. The mass spectrum contained a molecular ion peak. No other spectral measurements (lack of ORD, NMR) have been reported. For a thirty-six step synthesis in which each step may cause side-reaaions the characterization of the final product should, of course, be more elaborate. 

A soln of peptide 33 in degassed argon-sat. 50 mM NH4OAc buffer (pH 5.5) at 4 mM concentration was added dropwise to a 10 mM soln of 1 equiv of heterodimer 32 in 50 mM NH4OAc (pH 5.5) under exclusion of air oxygen. The reaction was monitored spectroscopically at 430 nm and by HPLC. After 2-3 h the solvent was removed and the product isolated by HPLC yield 35% the product was characterized by ESI-MS, HPLC, and amino add analysis. 

Of the 20 respondents, 19 use mass spectrometry for routine analysis of peptides, 16 use HPLC, and seven use amino add analysis. 

Disulfide linkages may be broken either oxidatively or reductively. The former method involves the treatment of the protein with performic add, which converts all disulfide bonds into cysteic add residues. This procedure is usually performed before a protein is hydrolyzed for amino add analysis. Cystine and cysteine are then determined as cysteic add. The reductive cleavage of disulfide bonds involves the treatment of the protein with mercaptoethanol (SH-CH2-CH2-OH), followed by the alkylation of the newly formed -SH groups. The complete disruption of all secondary interactions (that is, complete denaturation) can be achieved in most proteins with 6 M guanidine hydrochloride and 0.1 M mercaptoethanol or 8 M urea and 0.1 M mercaptoethanol. 

From proteins to proteomes - large-scale protein identification by 2-dimensional electrophoresis and amino-add-analysis. Bio-Technology 14, 61-65. 

Kofoed, J. and Reymond, J.L. (2007) A general method for designing combinatorial peptide libraries decodable by amino add analysis. Journal of Combinatorial Chemistry, 9,1046-1052. 

HASSAN AND HARE Amino Add Analysis in Bone Dating... 

Protein Sequencing, Peptide Synthesis, Amino Add Analysis and Mass Spectrometry - Methods for protein modification, proteolysis, RP-HPLC peptide purification and automated Edman degradation are well documented (7,10,14) as are methods for FMOC synthesis and myristylation of synthetic peptides (15) and amino acid analysis (16). 

Amino Add Analysis of Resin-Bound Peptide Mixtures ... 

Resin-bound peptide mixtures (each approx. 5 mg, approx. 10 000 beads) containing one mixture position, introduced by coupling a mixture of 18 amino acids in a predetermined molar ratio (see Section 4.3.7.1.2), were hydrolyzed in 50% propionic add/HCl at 130 °C for 2h. Each hydrolysate was then submitted to amino add analysis using a derivatizer-analyzer system (Applied Biosystems) in conjunction with PTH derivatization. Two samples of each peptide-resin were hydrolyzed and analyzed in parallel. 

The nonderivatized amino adds, following their chromatographic separation, can either be directly detected as free amino acids, on-line derivatized, or by postcolumn derivatization. Derivatization with ninhy-drin, the classical amino add analysis, was the first re-... 

R. M. Kamp, High sensitivity Amino add analysis, in Protein Structure Analysis (R. M. Kamp, T. Choli-Papa-dopoulou, and B. Wittman-Liebold, eds.), Springer-Verlag, Berlin, 1997. 

Amino Adds, Analysis by Means of Brdicka Reaction (Muller). 11 329... 

Extent of replacement of isoleucine as determined by amino add analysis. 

Soga, T., Heiger, D.N., Amino add analysis by capillary electrophoresis electrospray ionization mass spectrometry. AnaL Chem. 2000, 72, 1236. 

It is easily possible to include in a single polymer some proportion of each of the 20 amino adds common to modem protein, and to obtain a proteinoid that on hydrolysis gives an amino add analysis typical of proteins. 

Consider a simple example we are given a pentapeptide known to contain valine (two residues), leucine (one residue), histidine (one residue), and phenylalanine (one residue), as determined by hydrolysis and automatic amino add analysis. With this information we can write the molecular formula of the protein in the following way, using commas to indicate that the sequence is unknown ... 

Amino Add Analysis on Microscale from Electroblotted Proteins... 

P. Jandik. C. Pohl, V. Barreto and N. Avdalovic, Anion exchange chromatography and integrated amperometric detection of amino acids. In C. Cooper. N. Packer and K. Williams (eds.), Mahods in Molecular Biology, Vol. 159 Amino Add Analysis Protocols, Humana Press, Inc. Totowa, NJ, USA 2001. 

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