TY - JOUR
T1 - Covalent binding of acetaldehyde selectively inhibits the catalytic activity of lysine‐dependent enzymes
AU - Mauch, Teri J.
AU - Donohue, Terrence M.
AU - Zetterman, Rowen K.
AU - Sorrell, Michael F.
AU - Tuma, D. J.
N1 - Copyright:
Copyright 2016 Elsevier B.V., All rights reserved.
PY - 1986
Y1 - 1986
N2 - Hepatic ethanol metabolism generates the reactive intermediate, acetaldehyde, whichbinds to proteins. The binding of acetaldehyde to purified enzymes was determined in order to ascertain whether such binding altered their catalytic functions. [14C]Acetaldehyde was incubated with alcohol dehydrogenase, glucose‐6‐phosphate dehydrogenase, lactate dehydrogenase and RNase A, each at 37°C(pH 7.4). In some reactions, sodium cyanoborohydride was included for stabilization of Schiff bases, formed as a result of the reaction between acetaldehyde and the amino groups of the enzymes. Portions of each reaction mixture were removed for determination ofstable and total (stable plus borohydride‐reducible) adducts. Alcohol dehydrogenase and lactate dehydrogenase were not inhibited by adduct formation. Glucose‐6‐phosphate dehydrogenase and RNase, the activities of which depend on a lysine residue at their catalytic sites, were inhibited in a dose‐ and time‐dependent manner. The degree of inhibition directly correlated with total adduct formation. Phosphate, known to inhibit binding to the active site lysine of RNase, prevented the inhibition of catalytic activity caused by adduct formation. These findings indicate thatthe binding of acetaldehyde to lysine at the catalytic site can inhibit enzyme activity.
AB - Hepatic ethanol metabolism generates the reactive intermediate, acetaldehyde, whichbinds to proteins. The binding of acetaldehyde to purified enzymes was determined in order to ascertain whether such binding altered their catalytic functions. [14C]Acetaldehyde was incubated with alcohol dehydrogenase, glucose‐6‐phosphate dehydrogenase, lactate dehydrogenase and RNase A, each at 37°C(pH 7.4). In some reactions, sodium cyanoborohydride was included for stabilization of Schiff bases, formed as a result of the reaction between acetaldehyde and the amino groups of the enzymes. Portions of each reaction mixture were removed for determination ofstable and total (stable plus borohydride‐reducible) adducts. Alcohol dehydrogenase and lactate dehydrogenase were not inhibited by adduct formation. Glucose‐6‐phosphate dehydrogenase and RNase, the activities of which depend on a lysine residue at their catalytic sites, were inhibited in a dose‐ and time‐dependent manner. The degree of inhibition directly correlated with total adduct formation. Phosphate, known to inhibit binding to the active site lysine of RNase, prevented the inhibition of catalytic activity caused by adduct formation. These findings indicate thatthe binding of acetaldehyde to lysine at the catalytic site can inhibit enzyme activity.
UR - http://www.scopus.com/inward/record.url?scp=0022633847&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0022633847&partnerID=8YFLogxK
U2 - 10.1002/hep.1840060218
DO - 10.1002/hep.1840060218
M3 - Article
C2 - 2937708
AN - SCOPUS:0022633847
SN - 0270-9139
VL - 6
SP - 263
EP - 269
JO - Hepatology
JF - Hepatology
IS - 2
ER -