title: Purification and Characterization of Lactate Dehydrogenase in the Foot Muscle and Hepatopancreas of Otala lactea.
abstract: Lactate dehydrogenase (LDH) has a crucial role in maintaining ATP production as the terminal enzyme in anaerobic glycolysis. This study will determine the effect of posttranslational modifications (PTMs) on the activity of LDH in the foot muscle and hepatopancreas of an estivating snail, Otala lactea. LDH in foot muscle of O. lactea was purified to homogeneity and partially purified in hepatopancreas in a two-step and three-step process, respectively. The kinetic properties and stability of these isoforms were determined where there was a significant difference in Kmand I50values with pyruvate and urea separately in foot muscle; however, hepatopancreas exhibited significant differences in Kmand I50in salt between control and stress. Interestingly, hepatopancreas has a higher affinity for pyruvate in the control state whereas foot muscle has a higher affinity for its substrate in the estivated state. PTMs of each isoform were identified using immunoblotting and dot blots, which prove to be significantly higher in the control state. Overall, foot muscle LDH enters a low phosphorylation state during estivation allowing more efficiency in consuming pyruvate with higher thermal stability but less structural stability. Hepatopancreas LDH becomes dephosphorylated in the estivating snail that decreases the efficiency of the enzyme in the forward direction; however, the snail has an increased tolerance to the presence of salt when water becomes scarce. Such tissue-specific regulations indicate the organism's ability to reduce energy consumption when undergoing metabolic depression.
authors.affiliation: , 1125 Colonel By Dr, Ottawa, ON, K1S 5B6, Canada.
authors.forename: Isabelle A
authors.initials: IA
authors.lastname: MacLean
authors.affiliation: , 1125 Colonel By Dr, Ottawa, ON, K1S 5B6, Canada.
authors.forename: Amanda M S
authors.initials: AM
authors.lastname: Mattice
authors.affiliation: , 1125 Colonel By Dr, Ottawa, ON, K1S 5B6, Canada.
authors.forename: Nadine J
authors.initials: NJ
authors.lastname: Adam
authors.affiliation: , 1125 Colonel By Dr, Ottawa, ON, K1S 5B6, Canada. kenneth.storey@carleton.ca.
authors.forename: Kenneth B
authors.identifier: http://orcid.org/0000-0002-7363-1853
authors.initials: KB
authors.lastname: Storey
mesh_terms: D000818:Animals; D004795:Enzyme Stability; D004956:Estivation / Q000502:physiology; D043143:Hepatopancreas / Q000737:chemistry / Q000201:enzymology*; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000302:isolation & purification / Q000378:metabolism*; D009132:Muscles / Q000737:chemistry / Q000201:enzymology*; D009928:Organ Specificity; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D019289:Pyruvic Acid / Q000378:metabolism*; D012908:Snails / Q000737:chemistry / Q000201:enzymology*; D013379:Substrate Specificity; D014508:Urea / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D019289:Pyruvic Acid; D014508:Urea; D007770:L-Lactate Dehydrogenase
keywords: Enzyme regulation; Estivation; Glycolysis; Lactate dehydrogenase; Otala lactea; Posttranslational modifications