13 - Hemoglobin
from PART IV - MACROMOLECULES
Published online by Cambridge University Press: 05 August 2012
Summary
One of the primary functions of the red blood cell is to carry oxygen bound to hemoglobin. Hemoglobin can bind to a number of small molecules that affect its oxygen-carrying function. The binding of small molecules to a protein like hemoglobin can be described by chemical equations. All such chemical equations can be assembled into a stoichiometric matrix that describes all the bound states of the protein. Such a stoichiometric matrix can then be combined with another one that describes a metabolic network. In this chapter we describe the process that leads to an integrated kinetic description of low molecular weight metabolites and macromolecules, using hemoglobin as an example.
Hemoglobin: the carrier of oxygen
Physiological function and oxygen transport Red blood cells account for approximately 45% of the volume of the blood, a number known as the hematocrit. With a blood volume of 5 L, a “standard man” [112] has about 2.25 L of red blood cells, or a total of approximately 2.5 × 1013 red cells. Each red blood cell contains approximately 30 pg of hemoglobin.
Oxygen is carried in the blood in two forms: (1) dissolved in the plasma; (2) bound to hemoglobin inside the red blood cell. Oxygen is a nonpolar molecule that dissolves poorly in aqueous solution. Its solubility is only about 7 ppm at 37°C. Thus, 1 L of blood will only dissolve about 3.2 mL of oxygen.
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- Systems Biology: Simulation of Dynamic Network States , pp. 245 - 258Publisher: Cambridge University PressPrint publication year: 2011