We have described the most commonly used assay procedures determination of the DHLipDH activities from prokaryotic and eukaryotic cells. We have also described the procedures for the preparation of tissue extracts to determine the enzymatic activity. We have briefly alluded to the problems inherent in these assay procedures and suggested some precautions for using the assays to determine DHLipDH activity. We have also included a statement about the purification procedures and described some of the properties of this enzyme, which might help the reader in planning studies. We have, by no means, attempted to be comprehensive in this regard; therefore, the reader should consult the appropriate references (and references therein).