Mercapto-3-pentanone, 2-, formation

To explain the formation of 3-mercapto-2-pentanone without its 2,3-isomer, a new pathway was proposed (Scheme 5.15), in which 1,4-dideoxyosone and 5-hydroxy-3-mercapto-3-penten-2-one are intermediates. Both 2-methyl-3-furanthiol and 2-methyl-3-hydroxyfuran are readily derived from this pathway without involving norfuraneol. 

Scheme 5.15 Proposed formation of 3-mercapto-2-pentanone and 2-methyl-3-furanthiol from ribose and cysteine via l,4-dideoxy-2,3-diketose2X...

Fig. 3.23 Formation of 2-furfurylthiol, 2-methyl-3-furathiol, 3-mercapto-2-pentanone and 3-mercato-2-butanone from pentose and cysteine...

Kumazawa, K., Kubota, K., and Masuda, H. 2005. Influence of manufacturing conditions and crop season on the formation of 4-mercapto-4-methyl-2-pentanone in Japanese green tea (sen-cha). J. Agric. Food Chem. 53 5390-96. 

In this Section, I also include studies on protein glycation which is also known to produce protein folding disorders. This year, the structure of fructose-derived glycated products of Leu- and Met-enkephalin were established by NMR and their improved chemical and enzymatic stability in phosphate-buffered saline (pH 7.4) and human serum at 37 °C (over non-glycated) shown. In a similar study, the site specificity, extent and nature of modification of the tetrapeptide Leu-Ser-Lys-Leu incubated with D-Glc or D-Fru in methanol or phosphate buffer (pH 5.7, 7.4, 8.0) were compared for the production of Amadori (1-deoxy-D-fructosyl derivatives) and Heyne s rearrangement products (N-alkylated GlcN/ManN derivatives). Mannose and lauryl-mannoses (synthesised by lyase-catalysed condensation) were compared for the interaction with cysteine in Maillard product formation and 5-hydroxy-3-mercapto-2-pentanone was identified in the... 

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