Abstract

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.

Original languageEnglish (US)
Pages (from-to)263-269
Number of pages7
JournalHepatology
Volume6
Issue number2
DOIs
StatePublished - Jan 1 1986

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Acetaldehyde
Lysine
Enzymes
Catalytic Domain
Alcohol Dehydrogenase
Ribonucleases
Oxidoreductases
Pancreatic Ribonuclease
Schiff Bases
L-Lactate Dehydrogenase
Ethanol
Phosphates
Liver
Proteins

ASJC Scopus subject areas

  • Hepatology

Cite this

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title = "Covalent binding of acetaldehyde selectively inhibits the catalytic activity of lysine‐dependent enzymes",
abstract = "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.",
author = "Mauch, {Teri J} and Terrence Donohue and Zetterman, {Rowen K} and Sorrell, {Michael Floyd} and Tuma, {D. J.}",
year = "1986",
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doi = "10.1002/hep.1840060218",
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T1 - Covalent binding of acetaldehyde selectively inhibits the catalytic activity of lysine‐dependent enzymes

AU - Mauch, Teri J

AU - Donohue, Terrence

AU - Zetterman, Rowen K

AU - Sorrell, Michael Floyd

AU - Tuma, D. J.

PY - 1986/1/1

Y1 - 1986/1/1

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.

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U2 - 10.1002/hep.1840060218

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