Introduction

Abstract

For several years since the original observations (von der Helm, 1977; Yoshinaka and Luftig, 1977) that retroviruses encoded a proteolytic activity of their own, the retroviral proteases were rather enigmatic proteins, pushed into the background by their glamourous retroviral siblings, reverse transcriptase and the viral oncogenes. Nonetheless, the continuing interest and careful work of several key laboratories, progressively assembled a body of genetic and biochemical data which increasingly pointed to a very fundamental role for the protease in a retrovirus.