title: Purification and characterization of two distinct dipeptidyl aminopeptidases in soluble fraction from monkey brain and their action on enkephalins.
abstract: Two distinct dipeptidyl aminopeptidases, which were designated DPP-A and DPP-B, were purified from soluble fraction of monkey brain using Leu-enkephalin as the substrate. The enzymes were purified 187 and 136 fold, respectively. Both enzymes showed the optimum pH in neutral range. Their molecular weights were almost equal and were estimated to be about 100,000. Their Km values with Leu-enkephalin as the substrate were 5.6 X 10(-5) and 1.1 X 10(-5) M, respectively. Among synthesized substrates, the highest affinity of the enzymes was toward arginyl-arginine beta-naphthylamide with the Km values of 6.25 X 10(-5) and 6.41 X 10(-5) M, respectively. Both enzyme activities were inhibited by the metal-chelators DFP and PCMB. Two hundred fifty microM arphamenine A inhibited DPP-A and -B with inhibition of 36.6% and 44.1%, respectively. Beta-endorphin, ACTH, and glucagon inhibited only DPP-B, while beta-lipotropin and angiotensin II inhibited both DPP-A and -B when Leu-enkephalin was used as the substrate.
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology*; D003600:Cytosol / Q000201:enzymology; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000302:isolation & purification* / Q000378:metabolism; D010450:Endopeptidases / Q000302:isolation & purification*; D004743:Enkephalin, Leucine / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000378:metabolism*; D007700:Kinetics; D008252:Macaca fascicularis; D013379:Substrate Specificity
chemical_list: D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D010450:Endopeptidases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases