Transformation of Free and Dipeptide‐Bound Glycated Amino Acids by Two Strains of Saccharomyces cerevisiae

Abstract

The yeast Saccharomyces cerevisiae transforms branched-chain and aromatic amino acids into higher alcohols in the Ehrlich pathway. During microbiological culturing and industrial fermentations, this yeast is confronted with amino acids modified by reducing sugars in the Maillard reaction (glycation). In order to gain some preliminary insight into the physiological "handling" of glycated amino acids by yeasts, individual Maillard reaction products (MRPs: fructosyllysine, carboxymethyllysine, pyrraline, formyline, maltosine, methylglyoxal-derived hydroimidazolone) were administered to two strains of S. cerevisiae in a rich medium. Only formyline was converted into the corresponding α-hydroxy acid, to a small extent (10 %). Dipeptide-bound pyrraline and maltosine were removed from the medium with concomitant emergence of several metabolites. Pyrraline was mainly converted into the corresponding Ehrlich alcohol (20-60 %) and maltosine into the corresponding α-hydroxy acid (40-60 %). Five specific metabolites of glycated amino acids were synthesized and characterized. We show for the first time that S. cerevisiae can use glycated amino acids as a nitrogen source and transform them into new metabolites, provided that the substances can be transported across the cell membrane.

Probing Protein Glycation by Chromatography and Mass Spectrometry: Analysis of Glycation Adducts

“…Thereby, different experimental setups allow identification of individual modifications and quantification of glycation rates in proteins, as well as the products of their in vivo hydrolysis (so-called “glycation free adducts”) [ 74 ]. This workflow proved to be well-compatible with physiological experiments, performed at the molecular [ 87 ], cellular [ 88 ] or organism [ 76 ] levels, and applicable to in vitro model experiments and receptor affinity studies [ 89 ]. Whereas the early works addressed mostly simple model glycation systems (with consideration of only Amadori compound and CML as the major products), later studies employed multistep enzymatic hydrolysis protocols and covered a wide panel of glycation and oxidation products [ 74 ].…”

New Advanced Glycation End Products Observed in Rat Urine by Untargeted Metabolomics after Feeding with Heat‐Treated Skimmed Milk Powder

“…The aldehydes formed by decarboxylation can be transformed to the corresponding alcohol via dehydrogenases, or they could be oxidized to their corresponding acids. [ 39 ] Hence, the potential structures observed may result from common metabolic transformation pathways. [ 39 ] However, the resulting theoretical structures do not match with the spectra obtained by our two mass spectrometers.…”

“…[ 39 ] Hence, the potential structures observed may result from common metabolic transformation pathways. [ 39 ] However, the resulting theoretical structures do not match with the spectra obtained by our two mass spectrometers. Figure S8 depicts the inconsistent neutral losses from these two sources, showing the formation pathway in vitro and potential biotransformation in vivo for M10 as an example.…”

Anaerobic Degradation of N-ε-Carboxymethyllysine, a Major Glycation End-Product, by Human Intestinal Bacteria

“…Once aldehyde is formed, there is a possibility of a reduction of the aldehyde into the corresponding alcohol through the Ehrlich pathway. 33…”

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