Interdependence of coenzyme-induced conformational work and binding potential in yeast alcohol and porcine heart lactate dehydrogenases: a hydrogen-deuterium exchange study

Journal Article · Tue Jul 28 04:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00389a026· OSTI ID:5998246

De Weck, Z; Pande, J; Kaegi, J H.R.

Binding of NAD coenzymes to yeast alcohol dehydrogenase (YADH) and porcine heart lactate dehydrogenase (PHLDH) was studied by hydrogen-deuterium exchange with the infrared technique. Conformational changes in the enzymes specific to the coenzymes and their fragments were observed, and the pH dependence of the exchange reaction shows that it conforms to the EX-2 scheme. In both YADH and PHLDH the magnitude of the conformational change as measured by exchange retardation is considerably larger for the NAD/sup +/ than for NADH. Studies with coenzyme fragments like ADP-ribose, ADP, and AMP also highlight the lack of rigorous correlation between structural features such as charge and size and their influence on exchange behavior. Ternary complexes such as YADH-NAD/sup +/-pyrazole, PHLDH-NAD/sup +/-oxalate, and PHLDH-NADH-oxamate, which mimic the transition state, have a significantly more pronounced effect on exchange rates than the corresponding binary complexes. The outstanding feature of this study is the demonstration that in the binary enzyme-coenzyme complexes the more loosely bound NAD/sup +/ is more effective in retarding exchange than the more firmly bound NADH. These differences are attributed to the unequal structural constraints exerted by the two coenzymes upon the enzymes, which translate to unequal expenditure of transconformational work in the formation of the two complexes. The opposing variation in the free energy of binding and the transconformational work expended can be viewed as an unequal partitioning of the net free energy gain resulting from the protein-ligand interaction into a binding term and that required for conformational change.

• Research Organization: Universitaet Zuerich, Switzerland
• OSTI ID: 5998246
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:15; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION SPECTROSCOPY
ANIMALS
BODY
CARDIOVASCULAR SYSTEM
COENZYMES
CONFORMATIONAL CHANGES
DOMESTIC ANIMALS
ENZYMES
FUNGI
HEART
HEAVY WATER
HEMIACETAL DEHYDROGENASES
HYDROGEN COMPOUNDS
HYDROGEN TRANSFER
INFRARED SPECTRA
ISOTOPIC EXCHANGE
LACTATE DEHYDROGENASE
MAMMALS
MICROORGANISMS
ORGANS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PLANTS
SPECTRA
SPECTROSCOPY
SWINE
VERTEBRATES
WATER
YEASTS