Dipeptidyl aminopeptidase activities of guinea-pig brain.
1. The subcellular distribution of dipeptidyl aminopeptidase activities in guinea-pig brain was investigated. Our studies show that DAP I (Gly-Arg-NH-Mec hydrolase) type activity was found to have an acidic optimum and was associated with the nuclear pellet. 2. No DAP II (Lys-Ala-NH-Mec hydrolase) type activity could be detected. Apparent hydrolysis was mainly due to aminopeptidase activity. 3. DAP III (Arg-Arg-NH-Mec hydrolase) type activity is largely cytoplasmic, but there was evidence of a membrane form associated with the synaptosomes. 4. DAP IV (Gly-Pro-NH-Mec hydrolase) type activity is present on the synaptosomal membrane, and also enriched in the microsomes. A soluble form of Gly-Pro-NH-Mec hydrolase activity is also present in the cytoplasm. Whether this activity is a DAP II or IV type activity is still yet to be determined.
Smyth
M
M
Department of Biochemistry, University College, Galway, Ireland.
O'Cuinn
G
G
D000818:Animals; D001921:Brain / Q000201:enzymology*; D020789:Cathepsin C; D002458:Cell Fractionation; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism*; D006168:Guinea Pigs; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008861:Microsomes / Q000201:enzymology; D013574:Synaptosomes / Q000201:enzymology; D014021:Tissue Preservation
D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D020789:Cathepsin C; C100151:dipeptidyl peptidase II; C100152:dipeptidyl peptidase III; D018819:Dipeptidyl Peptidase 4