New Zealand Journal of Marine and Freshwater Research abstracts
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 (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.
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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