Kinetic analysis of duck epsilon-crystallin with L-lactate dehydrogenase activity: determination of kinetic constants and comparison of substrate specificity.
A systematic analysis of the kinetic properties of duck lens epsilon-crystallin with lactate dehydrogenase [LDH, (E.C. 1.1.1.27)] activity was carried out by employing some 19 different alpha-keto acids as substrates for this NADH-dependent LDH-catalyzed reaction. The steady-state Michaelis and catalytic constants (Km, kcat) were determined for a broad range of organic compounds. The results provide important insights regarding the binding and affinity of substrates to active sites of this enzyme crystallin and indicate a great potential for the application of the stable epsilon-crystallin as a catalyst to the synthesis of some important chiral alpha-hydroxyacids in a convenient and efficient way. It is also demonstrated for the first time that in addition to the enzymatic activity of lactate dehydrogenase, duck epsilon-crystallin also possesses the enzymatic activity of malate dehydrogenase.
Wu
C Y
CY
Graduate Institute of Biochemical Sciences, National Taiwan University, Taipei.
Chen
S T
ST
Chiou
S H
SH
Wang
K T
KT
D000818:Animals; D001665:Binding Sites; D002645:Chickens; D003459:Crystallins / Q000302:isolation & purification / Q000378:metabolism*; D004372:Ducks; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000302:isolation & purification / Q000378:metabolism*; D009132:Muscles / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D013379:Substrate Specificity
D003459:Crystallins; D007770:L-Lactate Dehydrogenase