DSB-X™ biotin hydrazide can be reversibly coupled to aldehydes and ketones to form a Schiff base - which can be reduced to a generate stable amine derivative by sodium borohydride (NaBH₄) or sodium cyanoborohydride (NaCNH₃). Carboxylic acids of proteins and other water-soluble biopolymers can be coupled to this molecule in aqueous solution using water-soluble carbodiimides such as EDAC (E2247). DSB-X™ biotin is a derivative of desthiobiotin, a stable biotin precursor. DSB-X™ biotin utilizes a seven-atom spacer to increase the available of the DSB-X™ biotin conjugate to bind in the deep biotin-binding pocket of streptpavidin or avidin. Whereas harsh chaotropic agents and low pH are required to dissociate a biotin complex from avidin or steptavidin, binding can be reversed by adding excess D-desthiobiotin or natural D-biotin at neutral pH and at room temperature.