Current Topics in Cellular Regulation: Volume 22 is a collection of papers that deals with eukaryotic protein synthesis, lysosomal thiol proteinases, and the properties of adenylosuccinate synthetase. Other papers discuss the regulation of acetyl-CoA carboxylase, ornithine cycle, and seminal vesicle development and function. One paper investigates the poly ADP-ribosylation of protein, particularly in quantifying synthesis and in the function of the polymer. Another paper observes the construction of a reconstituted cell-free system in which there is for the first time a catalytic use, followed by a recycling of eIF-2. A eukaryotic regulatory factor or eukaryotic recycling factor (eRF) is a prerequisite factor in the in the control of the rate of initiation. One paper reviews the properties, structures, and functions of thiol endopeptidases in mammalian lysosomes and the characteristics of the endogenous inhibitor. Another paper explains the regulatory, kinetic, and genetic aspects of adenylosuccinate synthetase from a variety of systems. One paper discusses the short-term regulation of the carboxylase from animal tissues, with emphasis on the covalent modification of the carboxylase, and its relationship to the allosteric control mechanism. Molecular biologists, general biologists, and microbiologists will find the articles in this collection invaluable.