Hüfner number

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The Hüfner number is the oxygen volume (O 2 ) that can be bound by 1 g of hemoglobin (Hb) in vivo , namely 1.34 ml under normal conditions , i.e. the maximum oxygen binding capacity.

The value is based on the fact that one molecule of hemoglobin can bind four molecules of oxygen. Taking into account the molar volume for ideal gases (approx. 22.4 l under normal conditions ), 1 mol of hemoglobin can thus absorb 89.6 l of oxygen, which is based on the molar mass of hemoglobin (approx. 64500 g / mol) in the theoretical in vitro Value of 1.39 ml O 2 / g Hb results. However, this value is not achieved even under optimal laboratory conditions. In addition, hemoglobin is physiologically present in small quantities as methemoglobin or CO-hemoglobin . These forms cannot bind oxygen, which is the reason for the lower in vivo value of 1.34 ml O 2 / g Hb.

The Hüfner number goes back to the chemist Gustav von Hüfner .

literature

  • R. Klinke, HC. Pape, St. Silbernagl: Physiology. Thieme, Stuttgart 2005, ISBN 3-13-796005-3 , p. 283.