Current Topics in Biochemistry 1973 is based on a series of lectures held at the National Institutes of Health dealing with biochemistry. This group of lectures is the most recent in a program, which was established in the mid-1960s, to review various research fields for the scientific community at the Institutes. The topics for these series were chosen to emphasize active fields of general interest for a diverse audience of scientists. The speakers were therefore encouraged to present an overview of their fields rather than a detailed discussion of current research problems. The lectures in present collection cover the following topics: the problem of predicting the conformation of a protein from a knowledge of its amino acid sequence; studies on the structure of glutamic dehydrogenase; immunologic approaches to the study of proteins; the NIH shift and its implications for the mechanism of biological oxidations; separation of transcribable and repressed chromatin; gene expression in animal cells; and plasma lipoproteins and apolipoproteins.