Comparison of tryptophan interactions to free and grafted BSA protein
The binding of d- and l-tryptophan molecules to bovine serum albumin (BSA) protein has been studied using liquid chromatography and ultrafiltration in the pH range from 7 to 11. A hydrophobic interaction between tryptophan and BSA has been observed at pH 7.0 on BSA grafted chromatographic column. Ho...
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Published in | Talanta (Oxford) Vol. 51; no. 5; pp. 1001 - 1007 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Amsterdam
Elsevier B.V
28.04.2000
Oxford Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | The binding of
d- and
l-tryptophan molecules to bovine serum albumin (BSA) protein has been studied using liquid chromatography and ultrafiltration in the pH range from 7 to 11. A hydrophobic interaction between tryptophan and BSA has been observed at pH 7.0 on BSA grafted chromatographic column. However, this interaction is negligible at higher pH for which the interaction to the stereospecific site was predominant. For both grafted and free proteins, the complexation mechanism was a competitive binding of
d- and
l-enantiomers on a single site. The apparent complexation constants for both
d- and
l-tryptophan show a maximum in the pH range 9–10. The variations of the apparent complexation constants versus pH were the result of the protonation of both the amino acid and a single site of the protein assuming that the complexation occurs between the zwitter-ionic amino acid form and the unprotonated BSA site. The apparent p
K
BSA is slightly shifted from 8.3 for grafted BSA protein to 9.4 for free BSA protein. This shift is presumably as a result of the different protein conformation. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0039-9140 1873-3573 |
DOI: | 10.1016/S0039-9140(99)00365-3 |