2-Iminobiotin is a cyclic guanidino analog of biotin that has high affinity for avidin at high pH (>9) and low affinity at low pH (<6). The proteins that are iminobiotinylated are selectively contained within the avidin column at pH 9 to 11 and may be eluted at pH 4 or by the addition of biotin. This technique may be very useful in the study of cell surface proteins by labeling and selectively recovering the components that are periodate-sensitive from intact human erythrocyte surface. 2-Iminobiotin reversibly inhibits NOS (nitric oxide synthases) via its guanidino group. It inhibits NO biosynthesis and may be important to understand the binding-site interactions for this important class of enzymes. NOS oxidizes the guanidino-nitrogen of L-arginine to produce nitric oxide and L-citrulline.
