A novel UDP-sugar, UDP-3-ketoglucosamine or UDP-4-ketoglucosamine, from bovine heart muscle reduces metmyoglobin with NAD(P)H.
3-Ketoglucose and similar ketosugars have been identified in microorganisms only and little is known about their functions. UDP-sugars are widely found as an intermediate in sugar metabolism in living organisms. Yet what role UDP-sugars play, or whether they play a direct role in metabolism, is still unknown. UDP-sugars were isolated and purified from bovine heart muscle, and a UDP-sugar fraction capable of NAD(P)H-dependent catalytic reduction of metmyoglobin was detected. Subsequent identification revealed that the active UDP-sugar was UDP-3- or UDP-4-ketoglucosamine. These compounds were purified from bovine cardiac muscle by ultrafiltration, anion-exchange column chromatography and reverse-phase chromatography. They were further characterized by determination of their chemical reducing activity, by comparison with synthetic UDP-3- or UDP-4-ketoglucosamine standards using high-performance liquid chromatography, by estimation of molecular mass using fast atom bombardment mass spectrometry, and by Fourier transform infrared microspectroscopy and electron probe microanalysis. The results suggest that UDP-3- or UDP-4-ketoglucosamine reduces metmyoglobin in bovine cardiac muscle. It is important that the reducing activity displayed by this ketosugar is not the effect of UDP-3- or UDP-4-ketoglucosamine alone but depends on NAD(P)H. In other words, this action of UDP-3- or UDP-4-ketoglucosamine is catalytic.
Kariya
M
M
Department of Biology, School of Education, Waseda University, Shinjuku-ku, Tokyo, Japan.
Sado
K
K
Namiki
H
H
D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D066298:In Vitro Techniques; D007700:Kinetics; D008786:Metmyoglobin / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D016339:Spectrometry, Mass, Fast Atom Bombardment; D014539:Uridine Diphosphate Sugars / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*
C110336:UDP-3-ketoglucosamine; C110335:UDP-4-ketoglucosamine; D014539:Uridine Diphosphate Sugars; D009243:NAD; D008786:Metmyoglobin; D009249:NADP