Avidin binding of radiolabeled biotin derivatives.
Three N-acyl derivatives of biotinylethylenediamine were prepared: I, biotinylamidoethyl-3-(3-[125I]iodo-4-hydroxyphenyl)propionamide; II, biotinylamidoethyl-[3H]acetamide; and III, biotinylamidoethyl-3-(3,5-[125I]diiodo-4-hydroxyphenyl)propionamid e. Each compound was combined with a large excess of avidin, yielding 1:1 molar complexes. Aside from a small fraction of each complex that dissociated more rapidly, the dissociation half-lives of these complexes were: I, 41 days; II, 4.4 days; and III, 148 days. The iodo- (mono or di) hydroxyphenylpropionyl moieties of I and III, therefore, contribute significantly to the binding strength of these compounds toward avidin. We also formed 4:1 complexes of I, II, and III with avidin (compound in excess), each of which exhibited biphasic dissociation, with initial half-lives of 4, 3.2, and 24 days, respectively. Thus, I or especially III potentially can be used as a sensitive tracer in quantitative studies with avidin.
Garlick
R K
RK
Department of Medicinal Chemistry, College of Pharmacy and Allied Health Professions, Northeastern University, Boston, Massachusetts 02115.
Giese
R W
RW
D000081:Acetamides / Q000378:metabolism; D001360:Avidin / Q000378:metabolism*; D001710:Biotin / Q000031:analogs & derivatives* / Q000378:metabolism*; D007202:Indicators and Reagents; D007457:Iodine Radioisotopes; D007700:Kinetics; D011485:Protein Binding; D011865:Radioisotope Dilution Technique; D013329:Structure-Activity Relationship; D014316:Tritium
D000081:Acetamides; D007202:Indicators and Reagents; D007457:Iodine Radioisotopes; D014316:Tritium; C064791:biotinylamidoethylacetamide; C064790:biotinylamidoethyl-3-(3-iodo-4-hydroxyphenyl)propionamide; C064792:biotinylamidoethyl-3-(3,5-diiodo-4-hydroxyphenyl)propionamide; D001360:Avidin; D001710:Biotin