TY - JOUR
T1 - Purification and characterization of enkephalin convertase, an enkephalin-synthesizing carboxypeptidase
AU - Fricker, L. D.
AU - Snyder, S. H.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1983
Y1 - 1983
N2 - Enkephalin convertase, an enkephalin-synthesizing carboxypeptidase present in adrenal medulla chromaffin granules, has also been detected in brain and pituitary. To determine whether these three carboxypeptidase activities represent the same enzyme, we purified and characterized enkephalin convertase from adrenal medulla, whole brain, and whole pituitary. Enzyme from all three tissues co-purifies on DEAE-cellulose, gel filtration, concanavalin A, and L-arginine affinity columns, resulting in a 135,000-fold, 110,000-fold, and 2,800-fold purification for bovine adrenal medulla, brain, and pituitary, respectively. Purified enkephalin convertase appears homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, showing a single band with an apparent molecular weight of 50,000 for enzyme isolated from all three tissues. Adrenal, brain, and pituitary enkephalin convertase are similarly inhibited by hexapeptide enkephalin precursors and active site-directed inhibitors. Both [Met]- and [Leu]enkephalin-Arg6 inhibit enkephalin convertase with K(i) values between 50 and 80 μM, while [Met]- and [Leu]enkephalin-Lys6 are 3-fold less potent. Two active site-directed inhibitors, guanidinopropylsuccinic acid and guanidinomercaptosuccinic acid, are potent inhibitors of all three enzymes with K(i) values of 8-9 nM. A series of dansylated di-, tri-, and tetrapeptide substrates are hydrolyzed by enkephalin convertase with similar kinetic properties (K(m), V(max), and K(cat)/K(m)) for the three enzymes. This evidence suggests that enkephalin convertase activity represents the same enzyme in adrenal medulla, brain, and pituitary. Enkephalin convertase may be involved in the production of other peptide neurotransmitters and hormones besides enkephalin.
AB - Enkephalin convertase, an enkephalin-synthesizing carboxypeptidase present in adrenal medulla chromaffin granules, has also been detected in brain and pituitary. To determine whether these three carboxypeptidase activities represent the same enzyme, we purified and characterized enkephalin convertase from adrenal medulla, whole brain, and whole pituitary. Enzyme from all three tissues co-purifies on DEAE-cellulose, gel filtration, concanavalin A, and L-arginine affinity columns, resulting in a 135,000-fold, 110,000-fold, and 2,800-fold purification for bovine adrenal medulla, brain, and pituitary, respectively. Purified enkephalin convertase appears homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, showing a single band with an apparent molecular weight of 50,000 for enzyme isolated from all three tissues. Adrenal, brain, and pituitary enkephalin convertase are similarly inhibited by hexapeptide enkephalin precursors and active site-directed inhibitors. Both [Met]- and [Leu]enkephalin-Arg6 inhibit enkephalin convertase with K(i) values between 50 and 80 μM, while [Met]- and [Leu]enkephalin-Lys6 are 3-fold less potent. Two active site-directed inhibitors, guanidinopropylsuccinic acid and guanidinomercaptosuccinic acid, are potent inhibitors of all three enzymes with K(i) values of 8-9 nM. A series of dansylated di-, tri-, and tetrapeptide substrates are hydrolyzed by enkephalin convertase with similar kinetic properties (K(m), V(max), and K(cat)/K(m)) for the three enzymes. This evidence suggests that enkephalin convertase activity represents the same enzyme in adrenal medulla, brain, and pituitary. Enkephalin convertase may be involved in the production of other peptide neurotransmitters and hormones besides enkephalin.
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M3 - Article
C2 - 6411723
AN - SCOPUS:0020513608
SN - 0021-9258
VL - 258
SP - 10950
EP - 10955
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 18
ER -