Cholera toxin: A paradigm of a multifunctional protein.

Cholera toxin (CT) was discovered exactly half a century ago by S.N. De. We have come a long way since this epoch-making discovery. Retrospectively, science had to wait a long time since Koch’s prediction of the existence of a toxin, and its actual discovery by De. CT is not just another enterotoxin that causes the signs and symptoms of the dreaded disease, cholera. It is unique in many respects, starting from its structure to its functions. CT is a multifunctional protein that is capable of influencing the immune system in many ways. It not only has remarkable adjuvant properties, but also acts as an anti-inflammatory agent, by modulating specific signal transduction pathways. Its immunomodulatory properties can be harnessed for treatment of various autoimmune disorders, and have shown great promise in the area of immunotherapeutics. CT can truly be considered as a paradigm of a multifunctional protein.

Photoaffinity labeling and photoaffinity crosslinking of enzymes

Photoaffinity labeling is a special type of chemical modification, where the label is activated by the action of light. This article presents the general principles and limitations of this technique, its application to the study of Micrococcus luteus ATPase and the use of photoaffinity crosslinking to probe the structure of this enzyme