Investigation of intermediates and transition states in the catalytic mechanisms of active site substituted cobalt(II), nickel(II), zinc(II), and cadmium(II) horse liver alcohol dehydrogenase

Journal Article · Tue Jan 12 00:00:00 EST 1982 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00531a024· OSTI ID:5672259

Dunn, M F ^[1]; Dietrich, H; MacGibbon, A K.H.; Koerber, S C; Zeppezauer, M

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1. Universitat des Saarlandes, Saarbrucken, West Germany

Active site substituted Co(II)-, Ni(II)-, and Cd(II)-horse liver alcohol dehydrogenase derivatives are compared to the native Zn(II)-enzyme with respect to the kinetic properties associated with the formation and decay of the intermediate observed in the reaction of the binary E-(NADH) complex with the intense substrate chromophore trans-4-(N,N-dimethylamino) cinnamaldehyde (DACA), lambda/sub max/ 398 nm (H/sub 2/O). All the metal ion subsituted enzymes were found to form intermediates with red-shifted spectra upon reaction with DACA and NADH. The magnitudes of (1) the red shifts, (2) the specific rate constants (k/sub off/) for dissociation of DACA from the intermediate, and (3) the hydride transfer rate constants (k /sub H/) were found to correlate with the expected order of the Lewis acid acidities (assuming tetrahedral coordination); i.e., Co(II) > Ni(II) greater than or equal to Zn(II) >> Cd(II). The k/sub H/ value for the Co(II)-E was found to be 1.4-fold greater than the value of 7.2 s/sup -1/ for Zn(II)-E, while the Cd(II)-E was40-fold lower. It is concluded that the close similarities in kinetic properties exhibited by Co(II)-, Ni(II)-, and Zn(II)-enzymes arise from the close similarities in coordination geometries and Lewis acid strengths which lead to highly similar transition states for the processes of intemediate formation and decay. (JMT)

• OSTI ID: 5672259
• Journal Information: Biochemistry; (United States), Vol. 21:2
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
59 BASIC BIOLOGICAL SCIENCES
CADMIUM
BIOLOGICAL EFFECTS
COBALT
NICKEL
OXIDOREDUCTASES
ENZYME ACTIVITY
ZINC
ALCOHOLS
BIOCHEMICAL REACTION KINETICS
HORSES
LIVER
ANIMALS
BODY
DIGESTIVE SYSTEM
ELEMENTS
ENZYMES
GLANDS
HYDROXY COMPOUNDS
KINETICS
MAMMALS
METALS
ORGANIC COMPOUNDS
ORGANS
REACTION KINETICS
TRANSITION ELEMENTS
VERTEBRATES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)
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