Thermal constraints on glycolytic metabolism in the New Zealand abalone,Haliotis iris: the role of tauropine dehydrogenase |
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| Authors: | Anthony J R Hickey Rufus M G Wells |
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| Institution: | 1. School of Biological Sciences , The University of Auckland , Private Bag 92 019, Auckland, New Zealand;2. School of Biological Sciences , The University of Auckland , Private Bag 92 019, Auckland, New Zealand E-mail: r.wells@auckland.ac.nz |
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| 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 (appKmpyr) 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 Vmax./appKmpyr, is close to 20°C. The possible thermal constraints on glycolytic metabolism in H. iris are discussed. |
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| Keywords: | abalone temperature metabolism tauropine dehydrogenase glycolysis Haliotis iris |
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