Amino Acids and Peptides

In the 1950’s Francis Crick formulated the “central dogma of molecular biology” in which information flows from DNA to RNA and finally to protein. Although certain exceptions to this model have emerged over the past 50 years, such as the discovery of RNA as the source of genetic information in certain viruses and the role of catalytic RNA in translation, this formulation has proved to be nearly ubiquitous. With this in mind it’s only appropriate to think of protein as the functional macromolecule of life; with DNA providing information storage and RNA acting as both decoder and messenger. However, as a consequence of this reality, proteins must be capable of performing an incredible number of both highly varied and highly specific tasks. For example, one protein must be capable of importing glucose across an impermeable cellular membrane while another protein must be capable of recognizing and catalyzing the phosphorylation of target macromolecules upon stimulation. Therefore, nature cleverly designed a single class of biomacromolecules capable of performing disparate functions. Among the varied responsibilities of proteins are molecular and ion transport, signaling, structural integrity, and reaction catalysis. Remarkably, nature has used many of the principles now common to you, as students of organic chemistry, to accomplish the extraordinary demands made of proteins.