ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The CD spectrum of an enzymatically derived sodium hyaluronate (NaHA) segment preparation with chain length 18 ± 3 disaccharide units [NaHAseg, ( NaGlcUA GlcNAc)15-20°. NaGlcUA, sodium D-glucuronate; GlcNAc, 2-acetamido-2-deoxy-D-glucose] in H2O was recorded to 180 nm using a computer-controlled vacuum-uv CD instrument. Near 190 nm the spectrum is of low intensity, similar to the sum of the free monosaccharide contributios, attributed to the π-π* transitions of the acetamido and carboxylate substituents. In contrast, much smaller oligosaccharides, also derived from high-molecular-weight NaHA by enzymatic digestions, show CD spectra in H2O with prominent bands centered near 190 nm. The oligosaccharide spectra can be matched as linear combinations of interior sugar residue (= NaHAseg) and end sugar residue CD contributions. End residues from oligosaccharides of the type (NaGlcUA-GlcNAc)n show a negative CD band near 190 nm. End residues from oligosaccharides of the reverse sequence (GlcNAc-NaGlcUA)n show a positive CD band near 190 nm. Averaging of the two end-residue spectral contributions yields an approximate match for the spectrum of NAHAseg below 200 nm. It is proposed that the low intensity CD of NaHA in the π-π* region is the result of large-magnitude, oppositely signed contributions, which can be visulized by studying oligosaccharides.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360220506
