New Zealand Journal of Marine and Freshwater Research abstracts

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Thermal constraints on glycolytic metabolism in the New Zealand abalone, Haliotis iris: the role of tauropine dehydrogenase

Anthony J. R. Hickey
Rufus M. G. Wells

School of Biological Sciences
The University of Auckland
Private Bag 92 019
Auckland, New Zealand
email: r.wells@auckland.ac.nz

Abstract  Black-foot abalone, Haliotis iris, were sampled from two populations in warm northern waters, and from two in colder southern waters. Abalone muscle is characterised by high activity of the glycolytic pyruvate reductase enzyme, tauropine dehydrogenase (TDH). Adductor muscle TDH was profiled for thermostability and activity to test the hypothesis that the enzyme may show adaptation in titre or kinetic characteristics reflecting thermal habitat. Temperature dependency of the apparent Michaelis-Menten constant of TDH for pyruvate (_appKm_pyr) suggested eurythermal enzyme behaviour below 20°C, and compromised function at the higher temperatures of northern populations occurring in the summer months. Thermostability profiles and enzyme activities suggest TDH expression does not differ significantly among populations (P > 0.05), indicating that this locus shows no compensation for temperature. The optimal temperature for efficient TDH function, estimated from V_max./_appKm_pyr, is close to 20°C. The possible thermal constraints on glycolytic metabolism in H. iris are discussed.

Keywords  abalone; temperature; metabolism; tauropine dehydrogenase; glycolysis; Haliotis iris

M03037 Received 11 July 2003; accepted 15 September 2003; Online publication date 31 October 2003
New Zealand Journal of Marine and Freshwater Research, 2003, Vol. 37: 723-731
0028-8330/03/3704-0723 $7.00 © The Royal Society of New Zealand 2003

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