Reaction of reduced disulfide bonds in α-lactalbumin and β-lactoglobulin with acrylonitrile

Quantitative assessment of cysteine and cystine in peptides and proteins following organomercurial derivatization and analysis by matrix-assisted laser desorption ionization mass spectrometry

“…ume rou s methods for the quantitative determination of free sulfhydryl groups (cysteine) and disulfide-bonds (cystine) in proteins are based on selective reactions in which thiols participate. The most precise and commonly used methods involve spectrophotometric titrations with mercaptide-forming compounds [1,2) or alkylating reagents [3,4], while others incorporate amino acid analysis following conversion of cysteine to cysteic acid [5) or to an alkyl derivative [4,6,7]. Major limitations in the spectrophotometric titration of macromolecular thiols are the relatively large sample size requirement (in the milligram range) and the uncertainty in determination of the end point.…”

A New Enzymatic Method of Acrylamide Production

“…hydratase and amidase of isobutyronitrile-grown P. chlororaphis B23 and acetonitrile-grown Arthrobacter sp. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] were measured (Table V). Nitrile hydratase of P. chlororaphis B23 was not specific for isobutyronitrile.…”

The Use of Acrylonitrile for the Subtractive Identification of the N-Terminal Residues of Small Peptides

“…Since extreme accuracy is not essential, methods involving separation on paper may be used, and a hydrolysate of the unmodified peptide can be run at the same time if required. The only side reactions appear to be the conversion of non-N-terminal lysine and cysteine into N6carboxyethyl-lysine and S-carboxyethylcysteine (Weil & Seibles, 1961;Friedman, Cavins & Wall, 1965) respectively.…”