Bioorganic chemistry

Author: H.Dugas
Publisher:
Publication Date: 1998-08-01
Features: Fragment: Chapter 1 Introduction to Bioorganic Chemistry
It might be helpful to remind ourselves of the incompleteness of our understanding, not only of ourselves (as individuals and us as a group) but also of Nature and the world around us. N. H. Hai-kerman Science 183, 907 (1974)
1.1 Basic Considerations
Among the first persons to develop bio-oriented organic projects was F. H. Westheimer. In the 1950s, he was probably the first physical organic chemist to do serious studies of biochemical reactions. However, it was only twenty-five years later that the field blossomed to what is now accepted as bioorganic chemistry. Bioorganic chemistry is a discipline that is essentially concerned with the application of the tools of chemistry to the understanding of biochemical processes. Such an understanding is often achieved with the aid of molecular models chemically synthesized in the laboratory. This allows a "sorting out" of the many variable parameters simultaneously operating within the biological system. For example, how does a biological membrane work? One builds a simple model of known compositions and studies a single behavior, such as an ion transport property. How does the brain work? This is by far more complicated than the previous example. Again, one studies single synapses and single synaptic constituents and then uses the observations to construct a model. Organic chemists develop synthetic methodology to better understand organic mechanisms and create new compounds. On the other hand, biochemists study life processes by means of biochemical methodology: enzyme purification and assay, radioisotopic tracer studies in in vivo systems. The former possesses the methodology to synthesize biological analogs but often fails to appreciate which synthesis would be relevant. The latter possesses an appreciation of what would be useful to synthesize in the laboratory but not the expertise to pursue the problem. The need for a multidisciplinary approach becomes obvious, and the bioorganic chemist will often have two laboratories: one for synthesis and another for biological study. A new dimension results from this combination of chemical and biological sciences, that is, the concept of model building to study and sort out the various parameters of a complex biological process. By means of simple organic models, many biological reactions as well as the specificity and efficiency of the enzymes involved have been reproduced in the test tube. The success of many of these models indicates the progress that has been made in understanding the chemistry operative in biological systems. Extrapolation of this multidisciplinary science to the pathological state is a major theme of the pharmaceutical industry—organic chemists and pharmacologists working "side by side," so that bioorganic chemistry is to biochemistry and medicinal chemistry is to pharmacology.
What are the tools needed for bioorganic model studies? Organic and physical organic chemical principles will provide, by their very nature, the best opportunities for model building—modeling molecular events that form the basis of life. A large portion of organic chemistry has been classically devoted to natural products. Many of those results have turned out to be wonderful tools for the discovery and characterization of specific molecular events in living systems. Think, for instance, of the development of antibiotics, certain alkaloids, and the design of new drugs for the medicine of today and tomorrow.
All living processes require energy, which is obtained by performing chemical reactions inside cells. These biochemical processes are based on chemical dynamics and involve reductions and oxidations. Biological oxidations are thus the main source of energy to drive a number of endergonic biological transformations. Many of these reactions involve the combustion of foods such as sugars and lipids to produce energy that is used for a variety of essential functions such as growth, replication, maintenance, muscular work, and heat production. These transformations are also related to oxygen uptake; breathing is a biochemical process by which molecular oxygen is reduced to water. Throughout these pathways, energy is stored in the form of adenosine triphosphate (ATP), an energy-rich compound known as the universal product of energetic transformations.