pH Regulation During Exercise

We all know that we need oxygen. It is breathed in through our lungs then “magically” transported to the blood stream where it is combined with fuel in the cells. Ultimately this gives us energy to fulfill our busy lives. A resting adult uses about 250 mL of pure oxygen pure minute, but only 1.5 percent of it is dissolved directly in the blood plasma. During exercise and work, the body uses more. The rest is transported by the hemoglobin in a metal complex called heme. Heme consists of iron complexes which transport oxygen to the cells and tissues. Through complex signaling the oxygen dock and undocks from the heme. Polypeptide chains are formed from amino acids and the metal complexes. In hemoglobin, the hydrogen-bonding interaction occurs between the H of an -NH group and the O of a -CO group of the polypeptide backbone chain. You’ll notice that these molecules are alkaline, they have a negative charge. So all interactions in the blood must help it return to its alkaline 7.365 to 7.425 range.

In 1904 Christian Bohn discovered that it was the increase in CO2 and H+ ions in the tissues that triggered the release of oxygen by the hemoglobin to which tissues required it the most. Known as the Bohr effect, it shows how the body’s blood gas exchange mechanism works. The oxygenated blood is pumped from the heart to the body cells because these tissues require oxygen  to move particularly during exercise. The more movement and exercise that happens, generates more CO2 and H+ stimulating the hemoglobin to carry the O2 there and release it where the highest concentrations of CO2 and H+ are. It is necessary for the oxygen to be bound to the hemoglobin until it gets to the oxygen depleted tissues. In the lungs, the reverse effect occurs: high concentrations of O2 cause the release of CO2 from hemoglobin. This is all done through what is called salt bridging. These salt bridges are interactions between positively and negatively charged amino acid residues. There’s that acid/alkaline thing again.

Drink Cerra Water which  will enhance athletic performance and endurance by making oxygen more  available  and  bring the body into an alkaline balance.

References:
Guex, N. and Peitsch, M.C. Electrophoresis,1997,18, 2714-2723. (SwissPDB Viewer) URL:  HYPERLINK “http://www.expasy.ch/spdbv/mainpage.htm” http://www.expasy.ch/spdbv/mainpage.htm.
Ji, X. et al. “Positive and negative cooperativities at subsequent steps of oxygenation regulate the allosteric behavior of multistate sebacylhemoglobin,” (1996) Biochemistry, 35, 3418. Hemoglobin PDB coordinates, Brookhaven Protein Data Bank.
Kavanaugh, J.S. et al. “High-resolution x-ray study of deoxyhemoglobin Rothschild 37beta trp->arg: a mutation that creates an intersubunit chloride-binding site,” (1992) Biochemistry, 31, 4111. Deoxyhemoglobin PDB coordinates, Brookhaven Protein Data Bank.
Kilmartin, J.V. “Interaction of haemoglobin with protons, CO 2, and 2,3-diphosphoglycerate,” (1976) Br. Med. Bull., 32, 209.
Persistence of Vision Ray Tracer (POV-Ray). URL:  HYPERLINK “http://www.povray.org” http://www.povray.org.
Royer Jr., W.E. “High-resolution crystallographic analysis of co-operative dimeric hemoglobin,” J. Mol. Biol., 235, 657. Oxyhemoglobin PDB coordinates, Brookhaven Protein Data Bank.
Stryer, L. Biochemistry, 4th ed. W.H. Freeman and Co., New York, 1995, p.