Kosakai M, Yosizawa Z
J Biochem. 1978 Oct;84(4):779-85. doi: 10.1093/oxfordjournals.jbchem.a132189.
The color yields with hexuronic acids and hexuronic acid-containing substances were studied by means of the carbazole method of Bitter and Muir with or without 0.025 M borate. The carbazole-borate to carbazole (CB/C) ratios thus obtained indicated not only the degree of the borate effects on the color yields with these materials but also the anomalous nature of some of these substances in the carbozole reaction. The present data indicate that the high color yield with heparin in the carbozole reaction may be due to the production of free amino groups from acid-labile sulfamino groups in the early stage of the reaction, resulting in suppression of protonation on the alpha-D-glucosaminidic oxygen atoms attached to the hexuronic acid residues in the molecule. Moreover, it is suggested that the degree of the unusual color yields in the carbazole reaction with glycosaminoglycans is greatly influenced by the anomeric configuration of the hexosaminyl linkages attached to the hexuronic acid residues in these polymers.
采用Bitter和Muir的咔唑法，在有或没有0.025M硼酸盐的情况下，研究了己糖醛酸和含己糖醛酸物质的颜色产率。由此获得的咔唑 - 硼酸盐与咔唑（CB/C）的比率不仅表明了硼酸盐对这些物质颜色产率的影响程度，还表明了其中一些物质在咔唑反应中的异常性质。目前的数据表明，咔唑反应中肝素的高颜色产率可能是由于在反应早期酸不稳定的磺氨基产生了游离氨基，从而抑制了分子中与己糖醛酸残基相连的α - D - 葡糖胺糖苷氧原子上的质子化。此外，有人认为，在与糖胺聚糖的咔唑反应中，异常颜色产率的程度受这些聚合物中与己糖醛酸残基相连的己糖胺基连接的异头构型的很大影响。
