A. Dikov et al., Histochemical method for dipeptidyl aminopeptidase II with a new anthraquinonyl hydrazide substrate, CELL MOL B, 46(7), 2000, pp. 1213-1218
A new method for the histochemical visualization of lysosomal aminopeptidas
e dipeptidyl peplidase II activity (DPP II) is developed. The substrate L-L
ys-L-Ala-5-chloro-1-anthraquinonylhydrazide-2HBr (Lys-Ala-CAH) is readily h
ydrolyzed by the enzyme to release 5-Cl-1-anthraquinonyIhydrazine (CAH). Th
e last compound is simultaneously coupled to an aromatic aldehyde, e.g 4-ni
trobenzaldehyde (p-NBA) or piperonal (3,4-methylenedioxybenzaldehyde; PPL),
to form a highly insoluble deeply colored hydrazone, marking the enzyme lo
cations. Using the new method, DPP II is successfully localyzed in tissue s
ections from different rat organs.