Гемоглобин

Описание

Haemoglobin, the oxygen-transport protein in the red blood cells, is a tetramer and each of the four chains contains a haeme group. It is interesting to note that the four haeme groups in haemoglobin do not operate independently. The release (and binding) of oxygen is a cooperative process, which means that the loss (uptake) of the first oxygen molecule triggers the release of the remaining three.
The current model for oxygen binding in haemoglobin and myoglobin can be explained in the following way. The deoxy form contains a high-spin Fe(II) centre, which, because of its size, does not form a plane with its four nitrogen donor atoms. Instead, it is located slightly above the plane, drawn towards the His residue. Once oxygen enters trans to the His residue, the iron centre is oxidised to a low-spin Fe³⁺ centre and O₂ is reduced to [O₂]^-. Both species contain an unpaired electron. The low-spin Fe³⁺ moves into the plane and pulls the His residue down. This affects the remaining protein chain and triggers the uptake/release of oxygen in the other three haeme groups.

Использование

Medicine, usually called hemoglobin.

Определение

The respiratory protein of the red blood cells, it transfers oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. Its affinity for carbon monoxide is >200 times that for oxygen. Hemoglobin is a conjugated protein of molec

Общее описание

Native hemoglobin from bovine erythrocytes. A major oxygen-transporting component of red blood cells that is also nitric oxide scavenger. Blocks carbachol-stimulated cGMP production. This preparation contains primarily Ferric-hemoglobin and must be reduced to the ferrous form to bind molecular oxygen. Note: this preparation contains primarily ferric-hemoglobin and must be reduced to the ferrous form to bind molecular oxygen.

Методы очистки

Purify it from blood using CM-32 cellulose column chromatography. [Matsukawa et al. J Am Chem Soc 107 1108 1985.] For the purification of the  and  chains see Hill et al. Biochemical Preparations 10 55 1963. Histones (from S4A mouse lymphoma). The purification of histones uses a macroprocess column, heptafluorobutyric acid as solubilising and ion-pairing agent and an acetonitrile gradient. [McCroskey et al. Anal Biochem 163 427 1987.]