Multifunctional activities of pickerel liver alcohol dehydrogenase

1993 ◽  
Vol 71 (9-10) ◽  
pp. 427-431 ◽  
Author(s):  
C. Stan Tsai ◽  
Loola S. Al-Kassim
Keyword(s):  
Alcohol Dehydrogenase ◽  
Kinetic Studies ◽  
Regulatory Function ◽  
Amino Acid Residues ◽  
Liver Alcohol Dehydrogenase ◽  
Dead End ◽  
Steady State Kinetic ◽  
Esterolytic Activity ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

A major isozyme of pickerel liver alcohol dehydrogenase has been purified to homogeneity. The enzyme, in addition to catalyze NAD(P)+-linked dehydrogenation of alcohols, also mediates dismutation of aldehydes and hydrolysis of esters. Steady-state kinetic studies and chemical modifications of the pickerel liver enzyme with respect to its esterolytic and dismutative activities were carried out. Pickerel liver alcohol dehydrogenase catalyzes hydrolyses of p-nitrophenyl esters via a Uni-Bi mechanism, with alkanoic acids as the last product released. Modifications of Cys and Lys suppress the esterolytic activity. A random mechansim with the formation of dead-end complexes is implicated for the dismutation of octanal catalyzed by pickerel liver alcohol dehydrogenase. Two amino acid residues, Cys and His, are involved in the dehydrogenation as well as dismutation reactions. The present study identifies a regulatory function of Lys for the multifunctional activities of liver alcohol dehydrogenase. When the Lys residue is specifically glucosylated, the dehydrogenase activity increases. Its esterase activity decreases, while the dismutase activity remains unchanged.Key words: multifunctionality, pickerel liver, alcohol dehydrogenase.

Purification and kinetic characterization of pickerel liver alcohol dehydrogenase with dual coenzyme specificity

1993 ◽  
Vol 71 (9-10) ◽  
pp. 421-426 ◽  
Author(s):  
Loola S. Al-Kassim ◽  
C. Stan Tsai
Keyword(s):  
Alcohol Dehydrogenase ◽  
Gel Filtration ◽  
Kinetic Studies ◽  
Resonance Spectroscopy ◽  
Coenzyme Specificity ◽  
Liver Alcohol Dehydrogenase ◽  
Steady State Kinetic ◽  
Dehydrogenase Isozyme ◽  
State Kinetic

A major alcohol dehydrogenase isozyme that displays dual coenzyme specificity has been purified from pickerel liver by ion-exchange, gel filtration, and affinity chromatographic procedures. The purified enzyme is chromatographically and electrophoretically homogeneous. It is dimeric and possesses common physical properties shared by other liver alcohol dehydrogenases. Phosphorus-31 nuclear magnetic resonance spectroscopy demonstrates that NADP+ binds to two coenzyme sites of the pickerel enzyme. Steady-state kinetic studies suggest that pickerel liver alcohol dehydrogenase catalyzes NAD(P)+-linked ethanol oxidation via a random pathway. While the NADP+ reduction involves the formation of an abortive complex at high NADP+ concentrations, the NAD+ reduction at low NAD+ concentrations follows an ordered Bi-Bi mechanism with NAD+ being the leading reactant.Key words: purification, pickerel liver, alcohol dehydrogenase.

Kinetic Studies with Liver Alcohol Dehydrogenase*

Biochemistry ◽  
1965 ◽  
Vol 4 (11) ◽  
pp. 2442-2451 ◽  
Author(s):  
Craig C. Wratten ◽  
W. W. Cleland
Keyword(s):  
Alcohol Dehydrogenase ◽  
Kinetic Studies ◽  
Liver Alcohol Dehydrogenase

scholarly journals Kinetics of tryptic hydrolysis of the arginine-valine bond in folded and unfolded ribonuclease T1

1984 ◽  
Vol 219 (2) ◽  
pp. 411-417 ◽  
Author(s):  
C N Pace ◽  
A J Barrett
Keyword(s):  
Kinetic Studies ◽  
Peptide Bond ◽  
Small Peptides ◽  
Ribonuclease T1 ◽  
Chemically Modified ◽  
Steady State Kinetic ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
State Kinetic ◽  
Tryptic Hydrolysis

We have used ribonuclease T1 and its chemically modified derivatives as substrates, and trypsin as proteinase, to investigate the kinetics of proteolysis of a specific peptide bond in the folded and unfolded conformations of a protein. Steady-state kinetic studies showed that Km = 0.27 mM and Kcat. = 2.45 s-1 for the tryptic hydrolysis of the Arg(77)-Val(78) peptide bond in unfolded ribonuclease T1. This Km is somewhat lower than, and the kcat. value similar to, values found for the tryptic hydrolysis of comparable bonds in small peptides. Our data for the initial velocity of hydrolysis of the Arg(77)-Val(78) bond in a solution of the folded protein indicate that the bond is at least 1700 times less rapidly hydrolysed in the folded than in the unfolded conformation of ribonuclease T1, and do not exclude the possibility that the bond is completely resistant to hydrolysis in the folded protein.

scholarly journals Kinetic and mechanistic studies of methylated liver alcohol dehydrogenase

1978 ◽  
Vol 173 (2) ◽  
pp. 483-496 ◽  
Author(s):  
C S Tsai
Keyword(s):  
Alcohol Dehydrogenase ◽  
Substrate Inhibition ◽  
Kinetic Studies ◽  
Primary Alcohols ◽  
Reductive Methylation ◽  
Factors Affecting ◽  
Liver Alcohol Dehydrogenase ◽  
Wide Range ◽  
Lysine Residues ◽  
Michaelis Constants

Reductive methylation of lysine residues activates liver alcohol dehydrogenase in the oxidation of primary alcohols, but decreases the activity of the enzyme towards secondary alcohols. The modification also desensitizes the dehydrogenase to substrate inhibition at high alcohol concentrations. Steady-state kinetic studies of methylated liver alcohol dehydrogenase over a wide range of alcohol concentrations suggest that alcohol oxidation proceeds via a random addition of coenzyme and substrate with a pathway for the formation of the productive enzyme-NADH-alcohol complex. To facilitate the analyses of the effects of methylation on liver alcohol dehydrogenase and factors affecting them, new operational kinetic parameters to describe the results at high substrate concentration were introduced. The changes in the dehydrogenase activity on alkylation were found to be associated with changes in the maximum velocities that are affected by the hydrophobicity of alkyl groups introduced at lysine residues. The desensitization of alkylated liver alcohol dehydrogenase to substrate inhibition is identified with a decrease in inhibitory Michaelis constants for alcohols and this is favoured by the steric effects of substituents at the lysine residues.

scholarly journals Contribution of buried distal amino acid residues in horse liver alcohol dehydrogenase to structure and catalysis

2018 ◽  
Vol 27 (3) ◽  
pp. 750-768 ◽  
Author(s):  
Karthik K. Shanmuganatham ◽  
Rachel S. Wallace ◽  
Ann Ting-I Lee ◽  
Bryce V. Plapp
Keyword(s):  
Amino Acid ◽  
Alcohol Dehydrogenase ◽  
Amino Acid Residues ◽  
Horse Liver Alcohol Dehydrogenase ◽  
Liver Alcohol Dehydrogenase ◽  
Horse Liver
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