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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/06/20 06:59:21」(JST)

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Carbaminohemoglobin (or Carbaminohaemoglobin, also known as carbhaemoglobin and carbohaemoglobin) is a compound of haemoglobin and carbon dioxide, and is one of the forms in which carbon dioxide exists in the blood. 10% of carbon dioxide is carried in blood this way (85% carried in blood as bicarbonate [hydrogen carbonate], 5% carried as free CO2, in solution).

Mechanism

When carbon dioxide binds to haemoglobin, carbaminohemoglobin is formed, lowering haemoglobin's affinity for oxygen via the Bohr effect. In the absence of oxygen, unbound haemoglobin molecules have a greater chance of becoming carbaminohaemoglobin. (The Haldane Effect relates to the increased affinity of de-oxygenated haemoglobin for H+: offloading of oxygen to the tissues thus results in increased affinity of the haemoglobin for carbon dioxide, and H+ - which the body wants to be rid of- which can then be transported to the lung for removal). Carbaminohemoglobin has a distinctive blue color that may contribute to the dark red color of deoxygenated venous blood (compared to bright, saturated red of oxygenated arterial blood), blue color of veins and the purplish or bluish color of tissues in hypoxia.

Hemoglobin can bind to four molecules of carbon dioxide. The carbon dioxide molecules form an amide linkage to the four terminal-amine groups of the four protein chains in the deoxy form of the molecule. Thus, one hemoglobin molecule can transport four carbon dioxide molecules back to the lungs, where they are released when the molecule changes back to the oxyhemoglobin form.

References

http://books.google.com/books?id=sKT2Sq4P0j8C&pg=PA431&lpg=PA431&dq=carbon+dioxide+does+not+bind+hemoglobin+at+the+same+site+as+oxygen&source=bl&ots=Y1Oi0bVbtB&sig=Jb6R_sJvGb5LtqB6jB0BXo_UmbA&hl=en&ei=08CNSqSkM6iRtgeI9rCCDg&sa=X&oi=book_result&ct=result&resnum=10#

External links

carbaminohaemoglobin at eMedicine Dictionary
carbaminohaemoglobin A at the US National Library of Medicine Medical Subject Headings (MeSH)

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English Journal

Simple accurate mathematical models of blood HbO2 and HbCO 2 dissociation curves at varied physiological conditions: evaluation and comparison with other models.

Dash RK1, Korman B, Bassingthwaighte JB.
European journal of applied physiology.Eur J Appl Physiol.2015 Aug 23. [Epub ahead of print]
PURPOSE: Equations for blood oxyhemoglobin (HbO2) and carbaminohemoglobin (HbCO2) dissociation curves that incorporate nonlinear biochemical interactions of oxygen and carbon dioxide with hemoglobin (Hb), covering a wide range of physiological conditions, are crucial for a number of practical applic
PMID 26298270

「酸素解離曲線」

　　[★]

英: oxygen dissociation curve, ODC
同: 酸素平衡曲線 oxygen equilibrium curve、酸素飽和曲線 oxygen saturation curve、酸素結合曲線 oxygen binding curve、ヘモグロビン酸素解離曲線 hemoglobin-oxygen dissociation curve
関: 酸素飽和度、ヘモグロビン

解離曲線の右方シフト (SP.651)

酸素親和性が低く、酸素を解離しやすい。末梢で酸素供給量は増す
1. 温度上昇

結合-解離へ以降は解離側に傾く

2. pH低下 (pH>6.5)

アルカリ性ボーア効果。CO₂の共存下で作用減弱。CO₂とH2が競合するので

H⁺･Hb+O₂　⇔　Hb･O₂+H⁺

3. P_CO2上昇

P_CO2上昇により、ヘモグロビンN末のα-NH₂にCO₂が結合してcarbaminohemoglobinを作る

1-3は発熱部位、pH低下、P_CO2が高いところでO₂を放出するわけで、合理的

4. Cl^-増加
5. 2,3-DPG増加

ATP増加

解離曲線の左方シフト (SP.652)

生理的

酸素親和性が高く、酸素を結合しやすい。末梢で酸素供給量は減る
1. 温度低下
2. pH上昇
3. P_CO2低下
5. 2,3-DPG減少

非生理的

CO中毒
メトヘモグロビン血症

亜硝酸塩の摂取

「カルバミノヘモグロビン」

　　[★]

英: carbaminohemoglobin, carbamino-Hb
同: カルバモイルヘモグロビン carbamoylhemoglobin, カルボヘモグロビン carbohemoglobin
関

血液による二酸化炭素輸送で、血中に溶解した二酸化炭素の一部がヘモグロビンのアミノ基と結合して形成する。
血液を介して運搬されるCO2の約20%がこの型である。
Hb-NHCOOH

匿名

検索

案内

案内

carbaminohemoglobin