Question about carbonic anhydrase deficiency

[johndoe3344]

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Why does CA deficiency in general cause respiratory acidosis?

The equilibrium is written as: CO2 + H2O <-> H+ + HCO3-

So if CA catalyzes the reaction to the right, shouldn't it cause alkalosis and not acidosis?

 

[6FX]

Why does CA deficiency in general cause respiratory acidosis?

The equilibrium is written as: CO2 + H2O <-> H+ + HCO3-

So if CA catalyzes the reaction to the right, shouldn't it cause alkalosis and not acidosis?

I'll take a shot at it. As far as I know, the direction is the critical thing here. This reaction exists in two differnt directions depending on what part of the body you're in. The respiratory system is the opposite reaction to the reaction in the blood. That being said, H+ is transported via an antiport system, causing an increase in H+ concentration.

 

[johndoe3344]

There we go!! Thanks a lot, it makes sense.

In tissues, the predominant direction is the forward direction. But in lungs you need to get rid of CO2, so the bicarbonate that's been travelling in the plasma needs to go back into the RBC to be converted into CO2, the opposite reaction.

So if CA is deficient, you'll just have all these H2CO3's floating around (--> H+ + HCO3-), causing a buildup of H+, resulting in acidosis.