POSTTRANSLATIONAL NONENZYMATIC MODIFICATION OF PROTEINS .1. CHROMATOGRAPHY OF MARKER ADDUCTS WITH SPECIAL EMPHASIS TO GLYCATION REACTIONS

Analytical methods for marker compounds formed during post-translation al modifications of proteins are reviewed. Only adducts arising either in vivo or under in vitro conditions simulating the in vivo situation s are discussed. All of these compounds stem from either the reaction of free amino groups (i.e., lysine, arginine or N-terminal amino acid) . In most cases the reactive counterpart is an aldehydic moiety contai ning endogenous compound; however, other functional groups containing metabolites are considered as well. The main demand put upon such mark er compounds is that they are stable in acid or enzymatic hydrolysis o r, alternatively, can be stabilized by simple sample pretreatment (e.g ., by reduction). Practically all categories of separation procedures can be applied provided that the chemical characteristics of a particu lar marker are adequately respected; frequently combination of two dif ferent separation procedures based on different principles must be use d. Because of the low level of such marker compounds under in vivo con ditions, an appropriate sample enrichment step must be involved. Empha sis is put upon the analysis of Amadori products, pentosidine (and pen tosidine related compounds), pyrraline, furosine, N-carboxymethylamino acids, amino acid hydantoins and stabilized dicarbonyl intermediates. (C) 1997 Elsevier Science B.V.