Thermodynamic and Structural Adaptation Differences between the Mesophilic and Psychrophilic Lactate Dehydrogenases.

ABSTRACT: The thermodynamics of substrate binding and enzymatic activity of a glycolytic enzyme, lactate dehydrogenase (LDH), from both porcine heart, phLDH (Sus scrofa; a mesophile), and mackerel icefish, cgLDH (Chamapsocephalus gunnari; a psychrophile), were investigated. Using a novel and quite sensitive fluorescence assay that can distinguish protein conformational changes close to and distal from the substrate binding pocket, a reversible global protein structural transition preceding the high-temperature transition (denaturation) was surprisingly found to coincide with a marked change in enzymatic activity for both LDHs. A similar reversible structural transition of the active site structure was observed for phLDH but not for cgLDH. An observed lower substrate binding affinity for cgLDH compar

SUBMITTER: Khrapunov S 

PROVIDER: S-EPMC5574168 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature