Hopes to develop apolipoproteins for diagnostic or, even better, therapeuticpurposes are growing. Areas of use may range from arterial disease to AIDS, fertilization programs, neurological or inflammatory disorders, and the like. However, these young members of the large family of circulating proteins still deserve careful study, both in terms of structural and functional properties and of their pathological changes. In addition, related molecules, in particular belonging to the family of enzymes, such as lipases and acyltransferases, offer exciting insight into the mechanisms of regulation...