In Search of New Biological Dimensions

IN SEARCH OF NEW BIOLOGICAL DIMENSIONS ALBERT SZENT-GYÔRGYI* When I was a young man, passing through Chicago, Carlson invited me to give a seminar. After my talk, the secretary handed me a check for fifty dollars, which was, then, much more than today and seemed to me a very great lot. I refused to accept it, but the secretary said that 1 could not refuse it, as Carlson would feel very badly about it. On my question as to where the money was coming from, I was told that it was Carlson's private money. "Why does he do this?" I asked. "Because he is a prince," was the secretary's answer. It was then I learned that there are princes who wear their crowns on their heads and princes who wear their crowns in their hearts. Carlson was one ofthe latter, and ever since it was of great encouragement to know that we all can be princes without having been reared in a golden cradle. Carlson's cradle must have been very simple indeed. Though we do not know what life is, we can distinguish between life and death, and will not have the least doubt that the cat is alive when it moves, has reflexes, and excretions. What is underlying these age-old signs oflife is the transformation ofchemical energy into mechanical, electrical, or osmotic work. We do not understand the mechanism ofany of these transformations. This ignorance is in sharp contrast to the brilliant successes that biochemistry has achieved in other fields—which suggests that there is something wrong, somewhere. Present biochemistry is based on the experience that ifwe pull a living system to pieces we arrive at atoms or molecules. So we have to study atoms and molecules to understand the living organism. No doubt atoms * The Institute for Muscle Research at the Marine Biological Laboratory, Woods Hole, Massachusetts . This paper was presented as the first Annual AntonJ. Carlson Lecture at the University of Chicago, February 21, 1961. 393 and molecules are the bricks ofthe building oflife, and we have to know about bricks ifwe want to understand a building. But will the study of bricksever telluswhat a Greek temple was, andwill the study ofmolecules ever tell us what the temple oflife is, which is our body? In order to understand the temple, we must attempt to connect the bricks to higher units—walls, columns, and the like—in the hope that eventually we may even approach the sanctuary. What I propose to do is to throw a fleeting glance on atoms and molecules and then try to connect them. In this first effort we will have to be very modest, limiting ourselves to first neighbors. Atoms are built ofa nucleus and electrons around it. The paths, Orbitals, on which these electrons can move have different shapes and correspond -**- (a) (b) Fig i to different "allowed" levels ofenergy, separated by "forbidden zones." We usually symbolize these energy levels by horizontal lines. The lower ones are occupied, as a rule, by a pair ofelectrons spinning in opposite directions, while the higher ones are unoccupied (Fig. ta). What interests us biochemists are the outer electrons on the highest occupied levels, which are involved in chemical reactions. Of the empty levels, the lowest one will be ofthe greatest interest. Ifan electron on the highest occupied orbital absorbs a photon, then it is "excited" by the absorbed energy, i.e., raised to a higher level (Fig. lb). Most molecules are formed by atoms sharing a pair ofthe outer electrons . We can describe the structure ofthese molecules with fair accuracy, by the current symbols of chemistry, by various letters (standing for the various sorts ofatoms), while their link we symbolize by dashes. Atoms 394 Albert Szent-Gyorgyi · New Biological Dimensions Perspectives in Biology and Medicine · Summer 1961 can also be connected by sharing two pairs ofelectrons, in which case we write two dashes and call it a "double bond." If, in a system, every second bond is a double bond, as in -C=C-C=C-C-, then we call the double bonds "conjugated." In this case, the second pair of electrons does not know whether it belongs to...