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Off-topic: Maybe it's just me, and this is not important in the least, but I have been always slightly irritated by the use of the term "proton" in chemistry w

Off-topic: Maybe it's just me, and this is not important in the least, but I have been always slightly irritated by the use of the term "proton" in chemistry which they use to denote the (positive) hydrogen ion. Two reasons: unlike "electron", the term "proton" belongs in physics exclusively and not chemistry which only deals with point-like nuclei carrying mass plus an electric charge, and the electron cloud; the other reason was that just like many - if not most - chemical elements, hydrogen has several isotopes, and it is conceivable that at least some of the ions may have a neutron in its nucleus.

JumpCrisscross 7y ago
> the use of the term "proton" in chemistry which they use to denote the (positive) hydrogen ion H+/K+ ATPase is a proton pump, not a hydrogen ion pump. It evolved to pump protons, and mostly pumps protons. > the term "proton" belongs in physics exclusively and not chemistry which only deals with point-like nuclei carrying mass plus an electric charge, and the electron cloud Lots of biological machinery fails with heavy hydrogen isotopes, including some proton pumps [1]. This is why heavy water is poisonous [2]. [1] https://tbiomed.biomedcentral.com/articles/10.1186/1742-4682-4-9 https://tbiomed.biomedcentral.com/articles/10.1186/1742-4682... [2] https://en.m.wikipedia.org/wiki/Heavy_water https://en.m.wikipedia.org/wiki/Heavy_water
- CamperBob2 7y ago
  I agree with the GP. Biology is chemistry, and the hydrogen electron shell is what's important in chemistry, not the nucleus. If the proton didn't act as a hydrogen nucleus, we wouldn't use the term PPI at all. Heavy water being (slightly) toxic doesn't have any bearing on the larger point.
  - Metacelsus 7y ago
    >hydrogen electron shell is what's important in chemistry, not the nucleus The kinetic isotope effect would like to have a word with you.
    - CamperBob2 7y ago
      Yes, there are extremely obscure corner cases in nature. The larger point, once again, stands.
  - JumpCrisscross 7y ago
    > the hydrogen electron shell is what's important in chemistry, not the nucleus H+/K+ ATPase is literally a case of a proton pump that pumps protons. It’s in a class of proton pumps that pump far less efficiently, biologically-meaningfully less efficiently, with heavier isotopes. The nuclear structure is relevant. “Hydrogen pumps” would be inaccurate. “Hydrogen ion pumps”, while practically fine, would be less precise. General use of the term proton for hydrogen ions is debatable. But this is ironically a case where it isn’t.

JumpCrisscross 7y ago

> the use of the term "proton" in chemistry which they use to denote the (positive) hydrogen ion H+/K+ ATPase is a proton pump, not a hydrogen ion pump. It evolved to pump protons, and mostly pumps protons. > the term "proton" belongs in physics exclusively and not chemistry which only deals with point-like nuclei carrying mass plus an electric charge, and the electron cloud Lots of biological machinery fails with heavy hydrogen isotopes, including some proton pumps [1]. This is why heavy water is poisonous [2]. [1] https://tbiomed.biomedcentral.com/articles/10.1186/1742-4682-4-9 https://tbiomed.biomedcentral.com/articles/10.1186/1742-4682... [2] https://en.m.wikipedia.org/wiki/Heavy_water https://en.m.wikipedia.org/wiki/Heavy_water

CamperBob2 7y ago
I agree with the GP. Biology is chemistry, and the hydrogen electron shell is what's important in chemistry, not the nucleus. If the proton didn't act as a hydrogen nucleus, we wouldn't use the term PPI at all. Heavy water being (slightly) toxic doesn't have any bearing on the larger point.
- Metacelsus 7y ago
  >hydrogen electron shell is what's important in chemistry, not the nucleus The kinetic isotope effect would like to have a word with you.
  - CamperBob2 7y ago
    Yes, there are extremely obscure corner cases in nature. The larger point, once again, stands.
- JumpCrisscross 7y ago
  > the hydrogen electron shell is what's important in chemistry, not the nucleus H+/K+ ATPase is literally a case of a proton pump that pumps protons. It’s in a class of proton pumps that pump far less efficiently, biologically-meaningfully less efficiently, with heavier isotopes. The nuclear structure is relevant. “Hydrogen pumps” would be inaccurate. “Hydrogen ion pumps”, while practically fine, would be less precise. General use of the term proton for hydrogen ions is debatable. But this is ironically a case where it isn’t.