Dermatan sulfate, /3-eliminative degradation

The endocyclic, enolacetal-forming, 8-eliminative degradation of dermatan sulfate (33) possesses only one other notable stereochemical feature, namely, the hexopyranuronate residue of this heteropolysaccharide is that of L-idopyranuronic acid, in which the C-5 proton and the C-4 leaving-group are both axially attached (as was proved with synthetic, model compounds, discussed later) in the JC(l) conformation. Therefore, the /8-eliminative degradation of dermatan sulfate can be accepted as being a diaxial procedure, as in 38. 

The stereospecificity of enzymes in both of these types (axial-equatorial and diaxial) of /3-eliminative degradation has already been indicated for the degradation of dermatan sulfate, only enzymes that had... 

---