Word: hemoglobin
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Cautious Encouragement. The Michigan team, led by Dr. Robert Nalbandian of Blodgett Memorial Hospital in Grand Rapids, owes its discovery to the work of another researcher, Makio Murayama of the National Institutes of Health. Murayama discovered that the sickle-cell shape is caused by an abnormal bonding between hemoglobin molecules in the red cells. Using this knowledge, Nalbandian's team decided to try urea, a waste substance produced by the normal human liver and excreted in the urine. As they knew, urea can dissolve certain types of molecular bonds. Their experiment worked: urea broke the bond between the hemoglobin...
Scientists have known for a long time that in large amounts the gas severely impairs the ability of the blood's hemoglobin to carry oxygen from lungs to tissues. The result is a loss of energy and a crippling of both mental and physical reactions. Inhaling the gas from auto exhaust has become a popular method of suicide. Now, because the highly industrialized Northern Hemisphere contains more than 90% of the world's CO, U.S. scientists are voicing new concern about its effects...
...Each hemoglobin molecule, Perutz found, consists of 10,000 atoms, of which four are iron atoms that have an affinity for oxygen. In the lungs, in the presence of oxygen, the hemoglobin molecule changes shape, moving each of the four iron atoms, which are located in separate "pockets" on its surface, to different positions. This change increases by 300 times the molecule's attraction for oxygen atoms, pulling four of them into combination with the iron atoms. It is only because there are 280 million hemoglobin molecules in each red corpuscle that the blood has sufficient oxygen-carrying capacity...
Bizarre Scheme. Perutz studied molecular structure by analyzing X-ray photographs of crystallized hemoglobin. Scattered and deflected by the atoms within, the X-rays form a pattern of light and dark spots on a film behind the crystal. By patient mathematical analysis of thousands of variations of this pattern (each produced by a Perutz technique of substituting mercury "tag" atoms for different atoms within the hemoglobin molecule), the structure of the complex molecule was carefully pieced together...
...diffident, Perutz began to probe the hemoglobin structure in 1937, after he came to Cambridge as a refugee graduate student. His work was interrupted during the war because he was interned as an enemy alien; then he was released to work on a bizarre and impractical scheme to tow Arctic ice islands into the North Atlantic to serve as airbases...