GA20705

AMCA-Glu-Glu-Lys-Pro-Ile-Ser-Phe-Phe-Arg-Leu-Gly-Lys(biotinyl)-NH₂

Also known as (4S)-5-[[(2S)-1-[[(2S)-1-[(2S)-2-[[(2S,3S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[(2S)-1-[[2-[[(2S)-6-[5-[(3aS,4S,6aR)-2-oxo-1,3,3a,4,6,6a-hexahydrothieno[3,4-d]imidazol-4-yl]pentanoylamino]-1-amino-1-oxohexan-2-yl]amino]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-5-carbamimidamido-1-oxopentan-2-yl]amino]-1-oxo-3-phenylpropan-2-yl]amino]-1-oxo-3-phenylpropan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-3-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-6-amino-1-oxohexan-2-yl]amino]-4-carboxy-1-oxobutan-2-yl]amino]-4-[[2-(7-amino-4-methyl-2-oxochromen-3-yl)acetyl]amino]-5-oxopentanoic acid

Specific substrate for cathepsin D (Km = 53 µM, kcat = 7·28 s?¹, kcat/Km = 0·14 µM?¹s?¹) with a single cathepsin cleavage site between the two Phe residues· It is flanked by an N-terminal AMCA-fluorophore (7-amino-4-methylcoumarin-3-acetic acid) and a C-terminal biotin moiety· After enzymatic hydrolysis the biotin-conjugated cleavage product and undigested substrate AMCA-EEKPISFFRLGK(Biotinyl)-amide can be removed with streptavidin-coated magnetic beads· The remaining fluorescent peptide in solution represents the amount of digested substrate· The versatility of this cathepsin D 'digest and pull down assay' is applicable for routine assays