Early photoinduced enzymes of photoinduced carotenogenesis in a Mycobacterium species.

Some nonphotosynthetic microorganisms synthesize carotenes in response to light. Previous experiments demonstrated that the enzymes necessary for the synthesis and metabolism of phytoene were photoinduced in a Mycobacterium sp. We now report that prephytoene pyrophosphate synthetase is also totally photoinduced. Geranylgeranyl pyrophosphate synthetase (prenyltransferase), which is present in dark-grown cells, is increased severalfold by photoinduction. The enzymes necessary for the synthesis of high molecular weight (C,, to CdO) polyprenyl pyrophosphates and isopentenyl pyrophosphate isomerase were unaffected by photoinduction. This is the first report of the photoinduction of enzymes acting prior to prephytoene pyrophosphate. These enzymes are not restricted to carotene synthesis.