pH and haemoglobin oxygen affinity in blood from the Antarctic cod Dissostichus mawsoni.
Blood pH in the antarctic cod (Dissostichus mawsoni) and in two Trematomus species, occlrring at --1-9 degrees C, is extremely high (approximately 8-2 to 8-3). This supports and extends Rahn's (1966) model for the temperature-pH relationship in cold-blooded vertebrates. The blood of D. mawsoni shows a low oxygen affinity (P50 approximately equal to 14-5 mmHg at pH 8-16 and -1-9 degrees C). Despite normal in vitro temperature and pH sensitivities, blood P50 increases only slightly when live fish are temperature-stressed (+ 4-0 degrees C), or become acidotic as a result of agitational stress (blood pH 7-71), primarily as a result of compensatory decreases in blood ATP levels. Oxygen-binding properties of 'stripped' (cofactor-free) solutions of D. mawsoni haemoglobin were measured in attempts to elucidate the molecular mechanisms involved in the function of the pigment.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D005399:Fishes / Q000097:blood*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010100:Oxygen / Q000097:blood*; D010108:Oxyhemoglobins / Q000378:metabolism*; D013696:Temperature
D010108:Oxyhemoglobins; D000255:Adenosine Triphosphate; D010100:Oxygen