Catalysis of CO2 reactions by lung carbonic anhydrase.
Catalysis of CO2 reactions by lung carbonic anhydrase.
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肺碳酸酐酶催化 CO2 反应。
DOI：
10.1152/jappl.1978.44.6.882
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
R. Klocke
中科院分区：
文献类型：
--
作者：
R. Klocke
在用碳酸氢盐溶液灌注的分离无血肺制剂中研究了稳态二氧化碳排泄。在所有研究条件下，添加乙酰唑酰胺后，二氧化碳的排泄量会迅速显着减少。排泄的 CO2 有两个来源：溶解在灌注液中的 CO2 和肺毛细血管中碳酸氢盐脱水产生的 CO2。这两种来源的相对量通过测量乙炔的同时排泄来确定。 CO2 产生速率的测定可以计算毛细血管血容量、平均毛细血管通过时间以及肺中存在的碳酸酐酶对 CO2 反应的催化程度。通过测量肺静脉引流中的血红蛋白浓度和碳酸酐酶活性，排除了血液碳酸酐酶对灌注液的污染。对照条件下稳态 CO2 产生与碳酸酐酶抑制的比较表明，血浆中的碳酸氢盐能够获得足够的肺碳酸酐酶，以五倍催化 CO2 水合-脱水反应。
Steady-state carbon dioxide excretion was studied in isolated bloodless lung preparations perfused with bicarbonate solutions. Addition of acetazolamide produced a prompt, significant decrease in the volume of excreted CO2 under all conditions studied. Excreted CO2 was derived from two sources: CO2 dissolved in the perfusate and CO2 produced by dehydration of bicarbonate in the pulmonary capillary. The relative quantity of these two sources was determined by measurement of the simultaneous excretion of acetylene. Determination of the rate of CO2 production permitted the calculation of capillary blood volume, mean capillary transit time, and the degree of catalysis of CO2 reactions by carbonic anhydrase present in the lung. Contamination of perfusate with blood carbonic anhydrase was ruled out by measuring hemoglobin concentration and carbonic anhydrase activity in pulmonary venous drainage. Comparison of steady-state CO2 production during control conditions and carbonic anhydrase inhibition indicated that bicarbonate in plasma has access to sufficient lung carbonic anhydrase to catalyze the CO2 hydration-dehydration reaction by a factor of five.