Carbon-13 Nuclear Magnetic Resonance Studies of the Biosynthesis of Hyaluronic Acid

The carbon-13 nuclear magnetic resonance (13C-NMR) spectrum of 13C-labeled hyaluronic acid (HA, 1a) was measured to clarify the origin of the carbon atoms of HA. 13C-Labeled HA (1a) was obtained from the cell surface of Streptococcus zooepidemicus #104 after administration of [1-13C]-D-glucose (2). The isolated HA, which had a molecular weight of more than one million, showed three signals in the 13C-NMR spectrum with no chemical degradation. The results revealed that [1-13C]-D-glucose (2) was incorporated into the [1-13C]-D-dlucuronic acid units and [1-13C]-N-[13CH3]acetamido-glucosamine units of HA (1a). The predicted biosynthetic pathway of HA was confirmed by this experiment.