Biotin Reagents for Antibody Pretargeting. 4. Selection of Biotin Conjugates for in Vivo Application Based on Their Dissociation Rate from Avidin and Streptavidin
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- 作者：D. Scott Wilbur ; Ming-Kuan Chyan ; Pradip M. Pathare ; Donald K. Hamlin ; Milah B. Frownfelter ; and Brian B. Kegley
- 刊名：Bioconjugate Chemistry
- 出版年：2000
- 出版时间：July 2000
- 年：2000
- 卷：11
- 期：4
- 页码：569 - 583
- 全文大小：391K
- 年卷期：v.11,no.4(July 2000)
- ISSN：1520-4812
文摘
An investigation was conducted to determine the affect of structural variation of biotin conjugates ontheir dissociation rates from Av and SAv. This information was sought to help identify optimal biotinderivatives for in vivo applications. Fifteen biotin derivatives were conjugated with a cyanocobalamin(CN-Cbl) derivative for evaluation of their "relative" dissociation rates by size exclusion HPLCanalysis. Two biotin-CN-Cbl conjugates, one containing unaltered biotin and the other containingiminobiotin, were prepared as reference compounds for comparison purposes. The first structuralvariations studied involved modification of the biotinamide bond with a N-methyl moiety (i.e., sarcosineconjugate), lengthening the valeric acid side chain by a methylene unit (i.e., homobiotin), and replacingthe biotinamide bond with thiourea bonds in two conjugates. The rate of dissociation of the biotin-CN-Cbl derivative from Av and SAv was significantly increased for biotin derivatives containingthose structural features. Nine additional biotin conjugates were obtained by coupling amino acids orfunctional group protected amino acids to the biotin moiety. In the conjugates, the biotin moiety andbiotinamide bond were not altered, but substituents of various sizes were introduced 
to thebiotinamide bond. The results obtained from HPLC analyses indicated that the rate of dissociationfrom Av or SAv was not affected by small substituents to the biotinamide (e.g., methyl,hydroxymethyl, and carboxylate groups), but was significantly increased when larger functional groupswere present. On the basis of the results obtained, it appears that biotin conjugates which retain anunmodified biotin moiety and have a linker molecule conjugated to it that has a small functionalgroup (e.g., hydroxymethylene or carboxylate) to the biotinamide bond are excellent candidates forin vivo applications. These structural features are obtained in the biotin amino acid conjugates: biotin-serine, biotin-aspartate, biotin-lysine, and biotin-cysteine. Importantly, these biotin derivatives canbe readily conjugated with other molecules for specific in vivo applications. In our studies, thesederivatives will be used in the design of new biotin conjugates to carry radionuclides for cancer therapyusing the pretargeting approach.
to thebiotinamide bond. The results obtained from HPLC analyses indicated that the rate of dissociationfrom Av or SAv was not affected by small substituents to the biotinamide (e.g., methyl,hydroxymethyl, and carboxylate groups), but was significantly increased when larger functional groupswere present. On the basis of the results obtained, it appears that biotin conjugates which retain anunmodified biotin moiety and have a linker molecule conjugated to it that has a small functionalgroup (e.g., hydroxymethylene or carboxylate) to the biotinamide bond are excellent candidates forin vivo applications. These structural features are obtained in the biotin amino acid conjugates: biotin-serine, biotin-aspartate, biotin-lysine, and biotin-cysteine. Importantly, these biotin derivatives canbe readily conjugated with other molecules for specific in vivo applications. In our studies, thesederivatives will be used in the design of new biotin conjugates to carry radionuclides for cancer therapyusing the pretargeting approach.