Rhodamine 110 labelled speciality peptides are used in the study of Caspases (Cysteine aspartate-specific proteases).
Caspases play essential roles in apoptosis (programmed cell death), necrosis, and inflammation. They are therefore important therapeutic targets in ischemia and Alzheimer’s disease, for example. Rhodamine 110 contains two amino groups available for bis-conjugation to the C-terminal end of a peptide or amino acid. When in this form, the molecule is essentially non-fluorescent.
Enzymatic cleavage of the first amino acid (or peptide) results in a mono-substituted Rhodamine 110 derivative with a 1000 fold increase in fluorescence intensity; enzymatic cleavage of the second amino acid (or peptide) gives a further 10 fold increase in intensity. These substrates are therefore ideally suited to evaluate inhibition of the enzymes.
Rhodamine 110 conjugated to charged amino acids are generally cell permeable. These non-pH dependant, Rhodamine labelled peptides emit in the green range, while competitor AMC and peptides emit in the blue range.