Separation of keratan-sulfate-derived disaccharides by high-performance liquid chromatography and postcolumn derivatization with 2-cyanoacetamide and fluorimetric detection.
In this paper, we report a rapid, sensitive, and quantitative procedure to conduct disaccharide compositional analyses of keratan sulfates (KS) by means of high-performance liquid chromatography (HPLC) separation and postcolumn derivatization with 2-cyanoacetamide and fluorimetric detection of products generated by hydrolysis of this glycosaminoglycan with Bacillus sp. keratanase II or Escherichia freundii endo-beta-galactosidase. Following E. freundii endo-beta-galactosidase digestion of bovine corneal KS, the monosulfated disaccharide glcNAc6sbeta(1-->3)gal, accounting for approximately equals 95% nmol and 50% yield products, is produced. On the contrary, bovine corneal KS treated with endo-beta-N-acetylglucosaminidase (keratanase II) from Bacillus sp. generates two major products, the monosulfated disaccharide galbeta(1-->4)glcNAc6s ( approximately equals 50% nmol product) and the disulfated disaccharide gal6sbeta(1-->4)glcNAc6s ( approximately equals 40% nmol product) for over 90% nmol products. These disaccharides are separated and readily determined within 30 min by using a linear-gradient strong anion-exchange separation. A linear relationship was found for the two purified disaccharides over a wide range of concentrations, from approximately equals 108 pmol, 50 ng, to 2,160 pmol, 1,000 ng, for the disaccharide galbeta(1-->4)glcNAc6s, and from 92 pmol, 50 ng, to 1,840 pmol, 1,000 ng, for the disaccharide gal6sbeta(1-->4)glcNAc6s. HPLC analysis was applied to the quantitative and qualitative determination of KS produced by 3T3-J2 murine fibroblasts in the cell medium. The amount of KS was found to be 2.80+/-0.34 microg/ml/10(6) cells and composed of approximately equals 71% nmol of disaccharide galbeta(1-->4)glcNAc6s and 18% nmol of the disulfated disaccharide gal6sbeta(1-->4)glcNAc6s having approximately equals 1.20 sulfate groups/disaccharide. Our data illustrate that the HPLC procedure reported represents an improved approach for the quantitative and compositional microanalyses of KS, especially applicable to experimentation involving small amounts ( approximately 50 ng) of this glycosaminoglycan and in relation to its biological function and pathological importance.
Volpi
Nicola
N
Department of Biologia Animale, University of Modena and Reggio Emilia, 41100 Modena, Italy. volpi@unimo.it
Maccari
Francesca
F
Ferrari
Stefano
S
Luca
Michele De
MD
Pellegrini
Graziella
G
D000118:Acetylglucosaminidase / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004187:Disaccharides / Q000302:isolation & purification*; D005470:Fluorometry; D006026:Glycoside Hydrolases / Q000378:metabolism; D007632:Keratan Sulfate / Q000737:chemistry*; D051379:Mice; D009570:Nitriles / Q000737:chemistry; D012680:Sensitivity and Specificity; D041701:Swiss 3T3 Cells
D004187:Disaccharides; D009570:Nitriles; D007632:Keratan Sulfate; D006026:Glycoside Hydrolases; C086950:keratanase II; C026093:keratan-sulfate endo-1,4-beta-galactosidase; D000118:Acetylglucosaminidase; C031594:2-cyanoacetamide