Synthesis of Compounds related to Inosine 5'-Phosphate and Their Flavor Enhancing Activity. IV. 2-Substituted Inosine 5'-Phosphates

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

“…To achieve this, a binary solution (pH 6.0) containing the test nucleotide (0.05 mmol/L) and MSG (3 mmol/L) in water (fixed sample) was compared to a series of aqueous solutions containing constant levels of MSG (3 mmol/L) and logarithmically Figure 1. Chemical structures of umami enhancing purine ribonucleotides: inosine 5 0 -monophosphate (5 0 -IMP, 1), guanosine 5 0 -monophosphate (5 0 -GMP, 2), xanthosine 5 0 -monophosphate (5 0 -XMP, 3), adenosine 5 0 -monophosphate (5 0 -AMP, 4), 2-mercaptoinosine 5 0 -monophosphate (5), 2-furfuryl-thioinosine 5 0 -monophosphate (6), N 2 -(3-methylthiopropyl)-guanosine 5 0 -monophosphate (7), N 2 -(3-methylthiopropanoyl)-guanosine 5 0 -monophosphate (8), N 2 -lactoylguanosine 5 0 -monophosphate (9), and N 2 -(1-carboxyethyl)-guanosine 5 0 -monophosphate (10).…”

5-Aminoimidazole-4-carboxamide ribotide transformylase-IMP cyclohydrolase from human CCRF-CEM leukemia cells: purification, pH dependence, and inhibitors

“…The coupling of these resonances was not first-order, and coupling constants were not determined. 2-Mercaptoinosine 5'monophosphate was synthesized from AICAR (0.11 mmol) and phenyl isothiocyanate by the method of Imai et al (1971). The yield was 50%, and the product was pure when analyzed by gradient anion exchange HPLC and had Amax values of 198 and 284 nm.…”

Flavor Activity of Sulfur-containing Compounds Related to Flavor Nucleotides

“…The former was about 3 times bitterer than the latter in terms of threshold level (Table I). At a concentration of 0.5 gjlOO ml, 5' -AMS, 5'-CMS, 5'-UMS, 3',5'-dADS and 3',5'-dTDS had no bitter taste. It is interesting that bitter taste was recognized only when phosphoryl group in the flavor nucleotides (IMP and GMP) was replaced by sulfuryl group, but not recognized when phosphoryl group in nonflavorous nucleotides was replaced by sulfuryl group, although there was an opposite relationship between nucleoside sulfates and nucleoside phosphates in terms of threshold level as follows: 5'-IMS < 5'-GMS and 5'-IMP>5'-GMP (Table I).…”

“…On the other hand, flavor activity of various derivatives of 5'-IMP and 5'-GMP has been studied. 2 -61 From the viewpoint of comparative flavor chemistry, the following findings are of special interest, because they suggest participation of sulfur in flavor activity: (i) flavor enhancing activities of 2-furfurylthio-5'-IMP and 6-mercaptopurine riboside 5'-phosphate (6-thio-5'-IMP) were about 17 times and 3.4 times that of 5'-IMP, respectively (Imai et a1 3 ) and Yamaguchi et al 41 ), and (ii) inosine 5'-monosulfate (5'-IMS) and guanosine 5'-monosulfate (5'-GMS) reported as bitter substances by Honjo et al 51 were new taste blind substances or double taste substances (Yamaguchi et al 61 ). We prepared, therefore, a number of S-containing compounds related to flavor nucleotides in order to elucidate the participation of sulfur in their flavor activity.…”