| Автор | MIURA, Retsu |
| Автор | TOJO, Hiromasa |
| Автор | FUJII, Shigeru |
| Автор | MIYAKE, Yoshihiro |
| Дата выпуска | 1984 |
| dc.description | The interaction between riboflavin and riboflavin binding protein (RBP) was studied by <sup>13</sup>C-NMR spectroscopy. The <sup>13</sup>C-NMR spectra of riboflavin selectively enriched at the 2-, 4-, 4a-, and 10a-positions and of (3-[<sup>13</sup>C]methyl)riboflavin were measured both in the free and RBP-bound forms. The <sup>13</sup>C signals of <sup>13</sup>C-enriched riboflavin or 3-methyiriboflavin bound to RBP are broader than those of the free form, reflecting the restriction of flavin mobility. The 2-, 4-, and 10a-<sup>13</sup>C signals of riboflavin show no pH-dependent shift in the neutral to acidic pH region either in the bound or free form but the 4a-<sup>13</sup>C signal of bound riboflavin shifts to lower field in the acidic pH region while that of the free form remains unshifted. The 2-, 4-, 4a-, and 10a-<sup>13</sup>C signals of free riboflavin exhibited pH-dependent change in the alkaline pH region with a pK value of about 10, in association with the N(3)-H deprotonatiori. The pH titration profile of the 2-, 4-, and 4a-13C signals of bound riboflavin indicates that the pK of N(3)-H is shifted substantially to the alkaline side when riboflavin is bound to RBP. The 3-methyl-<sup>13</sup>C signal of 3-methylribo- flavin shows no pH-dependent shift whether the compound is free or bound to RBP. The binding of riboflavin and 3-methylriboflavin was also studied spectrofluorometrically. The analysis of the pH dependence of the association constant revealed that one ionizable group in RBP with pK of about 5 and N(3)-H of riboflavin play important roles in the binding. We conclude that RBP preferentially binds the neutral, i.e., N(3)-protonated, form of riboflavin and that the neutral form in turn is stabilized by the hydrophobic environment of RBP surrounding the N(3) region of the bound riboflavin molecule. |
| Формат | application.pdf |
| Издатель | Oxford University Press |
| Копирайт | © Oxford University Press |
| Тема | Articles |
| Название | A <sup>13</sup>C-NMR Study on the Interaction of Riboflavin with Egg White Riboflavin Binding Protein |
| Тип | research-article |
| Electronic ISSN | 1756-2651 |
| Print ISSN | 0021-924X |
| Журнал | Journal of Biochemistry |
| Том | 96 |
| Первая страница | 197 |
| Последняя страница | 206 |
| Аффилиация | MIURA Retsu; Department of Biochemistry, National Cardiovascular Center Research Institute |
| Аффилиация | TOJO Hiromasa; Department of Biochemistry, Osaka University Medical School |
| Аффилиация | FUJII Shigeru; Department of Biochemistry, Osaka University Medical School |
| Аффилиация | MIYAKE Yoshihiro; Department of Biochemistry, National Cardiovascular Center Research Institute |
| Выпуск | 1 |
