Abstract
The keratan sulfate-containing proteoglycans were isolated from fourteen pooled human corneas (thirteen from 61- to 86-year-olds, plus one from a 12-year-old). These proteoglycans were subjected to digestion with the enzyme keratanase II, and the released oligosaccharides, which included nonreducing termini and repeat region oligosaccharides but not linkage regions, were reduced with alkaline borohydride and identified on two separate ion-exchange columns. Both of the latter had been calibrated with samples, most of which had been derived from bovine corneal keratan sulfate (Tai, G.-H., Huckerby, T. N., and Nieduszynski, I. A. (1996) J. Biol. Chem. 271, 23535-23546) and all of which had been fully characterized by NMR spectroscopic analysis. The capping structures identified in human corneal keratan sulfates occurred in the relative proportions: NeuAcalpha(2-6)- >NeuAcalpha(2-3)- >GalNAc(S)beta(1-3)-. The other groups of capping structures which had been identified in bovine corneal keratan sulfate, i.e. NeuGcalpha(2-3)-, NeuGcalpha(2-6)-, GlcNAc(S)beta(1-3)- were absent, although the possibility of the presence of some Galalpha(1-3)- structures could not be excluded. In addition, the human sample showed significantly higher levels of alpha(1-3)-fucosylated repeat region structures than did the bovine sample, and it is not clear whether this reflects a species or age dependence as the bovine corneas were from young animals, whereas the human corneas were predominantly from an older group. The charge densities and keratan sulfate chain sizes of the human and bovine keratan sulfate-containing proteoglycans were seen to be similar.
Highlights
The capping structures identified in human corneal keratan sulfates occurred in the relative proportions: NeuAc␣(2-6)- >NeuAc␣(2-3)- >GalNAc(S)(1-3)
General Discussion—Comparison of these results on human KSPGs with those from bovine cornea show that the proteoglycans have similar charge densities and keratan sulfate (KS) chain sizes
The similarity of KS chain size between human and bovine KSPGs is interesting in the light of the double-stranded glycosaminoglycan model (3), which has been proposed for controlling the regular collagen interfibrillar spacing
Summary
Vol 272, No 45, Issue of November 7, pp. 28227–28231, 1997 Printed in U.S.A. (Received for publication, February 28, 1997, and in revised form, July 22, 1997). The keratan sulfate-containing proteoglycans were isolated from fourteen pooled human corneas (thirteen from 61- to 86-year-olds, plus one from a 12-year-old). These proteoglycans were subjected to digestion with the enzyme keratanase II, and the released oligosaccharides, which included nonreducing termini and repeat region oligosaccharides but not linkage regions, were reduced with alkaline borohydride and identified on two separate ion-exchange columns. Despite the many structural studies there has been little investigation of human corneal keratan sulfate This investigation seeks to extend our previous work on bovine cornea (13), and it applies keratanase II fingerprinting methodology (14, 15) to the elucidation of the capping and repeat region structures in the entire population of human corneal KSPGs
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
