PNB 2250 Lecture Notes - Lecture 7: Special Circumstances, Carbonic Anhydrase, Ion Exchange
17 Sep 2016
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Physiological effects of co2: ph must be tightly controlled by air breathers, animals that move from water to land have big issues, adaptations for co2. Carbonic anhydrase: important evolutionary advance, one of the fastest enzymes in the forward direction. Slower in the backward direction: accelerates carbon dioxide conversion. Carbon dioxide is a major source of acid production in many animals. More co2 production more carbonic anhydrase: small animals have higher activity levels. High carbonic anhydrase content: 5 families of ca. Only commonality use of zinc in reaction centers: ca comparative physiology. Increase in turnover rate of ca with vertebrate evolution. Increase in oxygen consumption/co2 production: associated with appearance of an anion exchanger in the membrane. Required for chloride exchange across membrane (how animals get acid out of their cells; swap bicarbonate for chloride in the cell; h+ can be released from the cell [bohr effect] and taken elsewhere by hb molecules)
