Purification and properties of white muscle lactate dehydrogenase from the anoxia-tolerant turtle, the red-eared slider, Trachemys scripta elegans

Dawson, N. J. , Bell, R. A.V. and Storey, K. B. (2013) Purification and properties of white muscle lactate dehydrogenase from the anoxia-tolerant turtle, the red-eared slider, Trachemys scripta elegans. Enzyme Research, 2013, 784973. (doi: 10.1155/2013/784973) (PMID:23533717) (PMCID:PMC3594981)

Abstract

Lactate dehydrogenase (LDH; E.C. 1.1.1.27) is a crucial enzyme involved in energy metabolism in muscle, facilitating the production of ATP via glycolysis during oxygen deprivation by recycling NAD(+). The present study investigated purified LDH from the muscle of 20 h anoxic and normoxic T. s. elegans, and LDH from anoxic muscle showed a significantly lower (47%) K m for L-lactate and a higher V max value than the normoxic form. Several lines of evidence indicated that LDH was converted to a low phosphate form under anoxia: (a) stimulation of endogenously present protein phosphatases decreased the K m of L-lactate of control LDH to anoxic levels, whereas (b) stimulation of kinases increased the K m of L-lactate of anoxic LDH to normoxic levels, and (c) dot blot analysis shows significantly less serine (78%) and threonine (58%) phosphorylation in anoxic muscle LDH as compared to normoxic LDH. The physiological consequence of anoxia-induced LDH dephosphorylation appears to be an increase in LDH activity to promote the reduction of pyruvate in muscle tissue, converting the glycolytic end product to lactate to maintain a prolonged glycolytic flux under energy-stressed anoxic conditions.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Dawson, Dr Neal
• Authors: Dawson, N. J., Bell, R. A.V., and Storey, K. B.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Enzyme Research
• Publisher: Hindawi
• ISSN: 2090-0406
• ISSN (Online): 2090-0414
• Published Online: 21 February 2013
• Copyright Holders: Copyright © 2013 Neal J. Dawson et al.
• First Published: First published in Enzyme Research 2013: 784973
• Publisher Policy: Reproduced under a Creative Commons License