Substituted anthraquinone dyes for cellular stains and enzyme detection

A substituted anthraquinone dye of Formula 1:

• wherein:
• Ra and Rb are independently H, methyl, methoxy or a halogen;
• m and n are independently 0, 1, or 2;
• R1 and R2 are independently H;
• R3 and R4 are independently an alkanoyl having the formula of Formula 2, or an alkyl having the formula of Formula 3:
• where L1 is a link comprising 2-12 non-hydrogen atoms;
• X1 is a substituent selected from the group consisting of a substituted or unsubstituted amino, a substituted or unsubstituted amidino, a substituted or unsubstituted guanidino, a substituted or unsubstituted aminooxy, a substituted or unsubstituted hydroxylamino, a substituted or unsubstituted hydrazino, a C3-6 trialkylammonium, a substituted or unsubstituted, natural or unnatural amino acid with a free alpha- or beta-amine, where the amino acid is attached to L1 via an amide bond;
• L2 is a link comprising 2-12 non-hydrogen atoms;
• X2 is selected from the group consisting of a substituted or unsubstituted amino, a substituted or unsubstituted amidino, a substituted or unsubstituted guanidino, a substituted or unsubstituted aminooxy, a substituted or unsubstituted hydroxylamino, a substituted or unsubstituted hydrazino, a substituted or unsubstituted, natural or unnatural amino acid with a free alpha- or beta-amine, where the amino acid is attached to L2 via an amide bond;
• or
• X2 is a mono- or disubstituted amino, where the mono- or di-substituents and L2 and the nitrogen atom to which they are attached form at least one 3-7 membered saturated ring;
• or X2 is a substituted or unsubstituted amino and L2 comprises at least one moiety selected from the group consisting of an ether bond, an amide bond, a hydroxy and a saturated 3-7 membered ring;
• and
• at least one of X1 and X2 is a substituted or unsubstituted, natural or unnatural amino acid with a free alpha- or beta-amine, where the amino acid is attached to L1 or L2 via an amide bond.