description

In comparison to biotin (Ka = 1015 M-1) and desthiobiotin (Ka = 1011 M-1), the guanidino analog of biotin (= 2-iminobiotin) shows an even weaker binding affinity (Ka = 108 M-1) for avidin, which is, in addition, pH-dependent. At high pH (> 9), iminobiotin-tagged proteins bind to avidin conjugates with high affinity, but the avidin–iminobiotin complexes dissociate at low pH (~ 4) or via replacement upon addition of biotin. This allows the purification of the captured protein without denaturation releasing biologically functional, iminobiotinylated-proteins from the avidin conjugates. Besides, 2-Iminobiotin reversibly inhibits nitric oxide synthases (NOS). NOS oxidizes the guanidino-nitrogen of L-arginine resulting in L-citrulline and nitric oxide.

references

Iminobiotin affinitiy columns and their application to retrieval of streptavidin; K. Hofmann, S. W. Wood, C. C. Brinton, J. A. Montibeller, F. M. Finn; Proc. Natl. Acad. Sci. USA 1980; 77(8): 4666-4668. https://doi.org/10.1073/pnas.77.8.4666.

Voltammetric homogeneous binding assay of biotin without a separation step using iminobiotin labeled with an electroactive compound; K. Sugawara, N. Kamiya, G. Hirabayashi, H. Kuramitz; Anal Sci 2005; 21(8): 897-900. https://doi.org/10.2116/analsci.21.897.

The use of the 2-iminobiotin-avidin interaction for the selective retrieval of labeled plasma membrane components; G. A. Orr; J. Biol. Chem. 1981; 256(2): 761-766.