Mutarotation, Hydrolysis, and Rearrangement Reactions of Glycosylamines¹

Abstract

The mutarotation, hydrolysis, and rearrangement reactions of D-glucosylamine, D-mannosylamine, and D-xylosylamine have been studied, and rationalized on the basis of the formation of an intermediate, acyclic imonium ion. Rate constants are given for the hydrolysis reaction under various conditions. The formation of diglycosylamines is explained as a type of transamination in which a second molecule of the glycosylamine reacts with the first (in the imonium ion form) with the subsequent elimination of ammonia. Unsubstituted D-glucosylamine has been found to undergo an Amadori rearrangement in glacial acetic acid or in some of the methylenic compounds found by Hodge and Rist to be effective in the rearrangement of N-substituted glyeosylamines. Intramolecular mechanisms are suggested to account for the effectiveness of carboxylic

Proteins of unknown biochemical function - A persistent problem and a roadmap to help overcome it

“…The first two intermediates in riboflavin biosynthesis are reactive glycosylamines that can spontaneously break down to 5-phosphoribosylamine and Maillard products, which are highly reactive and harmful (Isbell and Frush, 1958;Foor and Brown, 1975;Fischer et al, 2004;Munanairi et al, 2007). Because riboflavin biosynthesis is not feedback regulated, intermediates 1 and 2 can potentially build up and cause harm to the cell via their decomposition (Foor and Brown, 1975;Fischer et al, 2004).…”

The structural feature surrounding glycated lysine residues in human hemoglobin

“…Fourteen and fifteen tryptic peptides are derived from α and β chains of human hemoglobin, respectively (4). We recovered 6 (α chain) and 8 (β chain) peptides: α chain; AT1 (peak number 2, residue number 1-7), AT3 (1,(12)(13)(14)(15)(16), AT4 (6, 17-31), AT5 (13,(32)(33)(34)(35)(36)(37)(38)(39)(40), AT6 (12,(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56), and AT11 (8,(93)(94)(95)(96)(97)(98)(99), and β chain; BT1 (peak number 3, residue number 1-8), BT4 (15,(31)(32)(33)(34)(35)(36)(37)(38)(39)(40), BT9 (14, 67-82), BT10 (11,(83)(84)(85)(86)…”

“…The formation of glycation sites in hemoglobin molecules is a consequence of its three-dimensional structure around these sites (15). The Amadori rearrangement, by which a reducing sugar is fixed on a protein, is accelerated with an acid-base catalyst (9,10,11,13). An imidazole group of a histidine residue is most likely to play a significant role in this reaction.…”

Subcellular Localization of a UDP-Glucose:Aldehyde Cyanohydrin β-Glucosyl Transferase in Epidermal Plastids of Sorghum Leaf Blades

“…Cellulysin was obtained from Calbiochem. f-DGlucosylamine was prepared by the method of Isbell and Frus,h (10). The 44-pm mesh nylon net was purchased from Cistron, Lebanon, PA, and the 20-pam mesh nylon net was from Tetko Inc., Elmsford, NY.…”