Purification and characterization of enkephalin-degradating enzymes from calf-brain striatum.
Enkephalinase A and B are extracted from Triton-X 100 washed calf-brain particles and purified by DEAE-cellulose chromatography. Both enzymes have identical Km values in their membrane-bound and soluble form. Enkephalinase A has a pH optimum at 6.9 and a Km for Leu-enkephalin of 20-25 microM, which hardly depends on the pH. Thiorphan and phosphate are purely competitive inhibitors of Enkephalinase A with Ki values of 3 nM and 1.5 mM respectively (pH = 6.85). Enkephalinase B is not affected by phosphate or thiorphan. It has a Km for Leu-enkephalin of 10 microM, a pH optimum of 7.0 and is inhibited by low concentrations of apolar dipeptides.
D000626:Aminopeptidases / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D000818:Animals; D002417:Cattle; D003342:Corpus Striatum / Q000201:enzymology*; D004151:Dipeptides / Q000494:pharmacology; D004743:Enkephalin, Leucine / Q000378:metabolism; D007700:Kinetics; D015244:Thiorphan; D008625:Tiopronin / Q000031:analogs & derivatives / Q000494:pharmacology; D014018:Tissue Distribution
D004151:Dipeptides; D004743:Enkephalin, Leucine; D015244:Thiorphan; D008625:Tiopronin; D000626:Aminopeptidases; C025579:enkephalin degrading enzyme