[52] Formation of GDP-d-rhamnose and GDP-d-talomethylose from GDP-d-mannose

摘要: Publisher Summary This chapter discusses the formation of galactokinase diphosphogalactose (GDP-glactose)-D-Rhamnose and GDP-D-Talomethylose from GDP-D-Mannose. An enzyme preparation that catalyzes synthesis GDP-D-rhamnose (GDPR) GDP-D-talomethylose (GDPT) GDP-α-D-mannose (GDPM) is obtained an unclassified bacterium isolated soil after sonic disruption. There are two ways measuring overall reaction: (1) net methylpentose measured in presence crude enzyme, GDPM, a triphosphopyridine nucleotide (TPNH)-generating system; (2) GDPM-stimulated oxidation substrate quantities TPNH spectrophotometrically at room temperature 340 m μ GDPM. The conversion GDPM to GDPR GDPT involves GDP-4-keto-D-rhamnose (GDP-KR) as intermediate its subsequent reduction TPNH. fraction involved (GDP-KR reductase) purified 25-fold by diethylaminoethyl (DEAE)-cellulose column chromatography free converts (GDPM dehydrase). D-rhamnose D-talomethylose identified, acid hydrolysis, paper specific reactions.