AVIDIN DERIVATIVES AND USES THEREOF

A compound of formula (I) wherein R is H or -N=N-2-carboxyphenyl; A is (CH2)n or -CH=CH-, wherein n is an integer from 0 to 10, or A may also be -CH(COOH)- when R is -N=N-2-carboxyphenyl; and X is a radical selected from the group consisting of: (i) Cl; (ii) COOR1, wherein R1 is p-nitrophenyl or N-succinimidyl; (iii) CONH-NHR2, wherein R2 is H, COO(tbutyl) or COObenzyl; (iv) CONH-[B]-NHR3, wherein R3 is H, COOR1, or CO-[B']-maleimido, wherein R1 is t-butyl, pnitrophenyl or N-succinimidyl, and B and B', the same or different, are (CH2)n wherein n is an integer from 2 to 10; (v) CONH- [B]- COOR4, wherein R4 is H, C1-C8 alkyl, N-succinimidyl; (vi) CONH-[B]-OH; (vii) CONH-[B]-CONH-NHR2, wherein R2 is H, COO(t-butyl) or COObenzyl; and (viii) NHR2, wherein R2 is H, COO(t-butyl) or COObenzyl, when A is -CH(COOH)- and R is -N=N-2-carboxyphenyl. The 4'-hydroxyazobenzene-2-carboxylic acid (HABA) compounds are novel reagents for labeling, isolation and detection of biological molecules.