Abstract
Butyrylcholinesterase in human plasma and acetylcholinesterase in human red blood cells have aryl acylamidase activity toward o-nitroacetanilide, hydrolyzing the amide bond to produce o-nitroaniline and acetate. People with a genetic variant of butyrylcholinesterase that had no detectable activity with butyrylthiocholine, nevertheless had aryl acylamidase activity in their plasma. To determine the source of this aryl acylamidase activity we tested fatty acid free human albumin for activity. We found that albumin had aryl acylacylamidase activity and that this activity was inhibited by diisopropylfluorophosphate. Since the esterase activity of albumin is also inhibited by diisopropylfluorophosphate, and since it is known that diisopropylfluorophosphate covalently binds to Tyr 411 of human albumin, we conclude that the active site for aryl acylamidase activity of albumin is Tyr 411. Albumin accounts for about 10% of the aryl acylamidase activity in human plasma.
Original language | English (US) |
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Pages (from-to) | 186-188 |
Number of pages | 3 |
Journal | Archives of Biochemistry and Biophysics |
Volume | 452 |
Issue number | 2 |
DOIs | |
State | Published - Aug 15 2006 |
Externally published | Yes |
Keywords
- Albumin
- Aryl acylamidase
- Silent butyrylcholinesterase
- Tyr 411
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology