Discovery of N²-(1-Carboxyethyl)guanosine 5′-Monophosphate as an Umami-Enhancing Maillard-Modified Nucleotide in Yeast Extracts

Abstract

Sensory-guided fractionation of a commercial yeast extract involving medium-pressure RP-18 chromatography and ion-pair chromatography, followed by LC-MS/MS, LC-TOF-MS, 1D/2D-NMR, and CD spectroscopy, led to the discovery of the previously not reported umami-enhancing nucleotide diastereomers (R)- and (S)-N(2)-(1-carboxyethyl)guanosine 5'-monophosphate. Model experiments confirmed the formation of these diastereomers by a Maillard-type glycation of guanosine 5'-monophosphate with dihydroxyacetone and glyceraldehyde, respectively. Sensory studies revealed umami recognition threshold concentrations of 0.19 and 0.85 mmol/L for the (S)- and (R)-configured diastereomers, respectively, and demonstrated the taste-enhancing activity of these nucleotides on monosodium l-glutamate solutions.

Systematic Studies on the Chemical Structure and Umami Enhancing Activity of Maillard-Modified Guanosine 5′-Monophosphates

“…This lactamide was proposed to be formed upon the reaction of GMP (2) with lactic acid and was reported to exhibit pronounced umami enhancing activity (14). Very recently, sensory-directed fractionation of commercial yeast extracts revealed (R)-and (S)-N 2 -(1-carboxyethyl)-guanosine 5 0 -monophosphate, (R)-10 and (S)-10 ( Figure 1), as previously not reported umami enhancing nucleotides (15). Model experiments confirmed the formation of these diastereomers by a Maillard-type glycation of guanosine 5 0 -monophosphate (2) with the reactive C 3 -carbohydrates dihydroxyacetone and glyceraldehyde (15).…”

“…Very recently, sensory-directed fractionation of commercial yeast extracts revealed (R)-and (S)-N 2 -(1-carboxyethyl)-guanosine 5 0 -monophosphate, (R)-10 and (S)-10 ( Figure 1), as previously not reported umami enhancing nucleotides (15). Model experiments confirmed the formation of these diastereomers by a Maillard-type glycation of guanosine 5 0 -monophosphate (2) with the reactive C 3 -carbohydrates dihydroxyacetone and glyceraldehyde (15). Although some advanced glycation end products of the DNA base 2 0 -deoxyguanosine were identified in the past (16)(17)(18), the Maillard reaction products of the RNA base 5 0 -GMP (2) and, in particular, their putative umami modulating activity have not yet been investigated.…”

Sensomics Analysis of Taste Compounds in Balsamic Vinegar and Discovery of 5-Acetoxymethyl-2-furaldehyde as a Novel Sweet Taste Modulator

“…22,24 Aimed at decoding the typical taste signature of food products on a molecular level, the so-called taste dilution analysis (TDA) was developed as an efficient screening tool enabling the sensory-directed identification of dietary key tastants 22,23,25−29 as well as taste modulating compounds in foods such as, e.g., γ-glutamyl peptides in cheese and beans, 30,31 N-(1-methyl-4-oxoimidazolidin-2-ylidene)-α-amino acids in stewed beef, 32 and N 2 -(1-carboxyethyl)guanosine 5′-monophosphate in yeast extract, 33 respectively.…”

Human Taste and Umami Receptor Responses to Chemosensorica Generated by Maillard-type N2-Alkyl- and N2-Arylthiomethylation of Guanosine 5′-Monophosphates

“…12,13 Furthermore, amidation of the side chain's carboxy group induced a further increase of sensory activity of 10; for example, butylation revealed the high-potency umami enhancer 11. 14 Since the presence of sulfur atoms in synthetic N 2 -alkylated nucleotides was described to be beneficial for sensory activity, 6−10 the following experiments targeted the substitution of the exocyclic amino function of guanosine 5′-monophosphate (2) with formaldehyde, the Strecker aldehyde of glycine, and alkyl-and arylmercaptans, respectively, by means of Maillard-type reaction chemistry following the scheme depicted in Figure 2.…”

“…12 Intriguingly, only the (S)-configured nucleotide 10 showed a high β-value of 7.0 while the corresponding (R)-isomer showed only marginal sensory activity, 12 again demonstrating that small structural changes impact on the umami taste-enhancing activity of this molecule. To further widen the portfolio of Maillard-type modified derivatives of nucleotide 2, the N 2 -(1-carboxyethyl)guanosine 5′-phosphate scaffold was further altered by amidation of the side chain's carboxy group, thus leading to butylated (11) and isobutylated ribonucleotides (12) with an increased β-value of 7.6. 13,14 These results were verified both by human psychophysical as well as cell-based T1R1/ T1R3 receptor assays.…”