Hydrogenases and hydrogen metabolism in photosynthetic prokaryotes

Abstract

Hydrogen plays important, different roles in a variety of photosynthetic prokaryotes. The variety of different hydrogenases, their catalytic sites, maturation, and genetic organization are reviewed in the context of what is known about these enzymes from model non-photosynthetic organisms. Examples from specific cyanobacteria and various anoxygenic photosynthetic bacteria are discussed in detail along with what is known about their metabolic role. The latest findings on transcriptional regulators and the metabolic conditions that regulate the expression of hydrogenases in various photosynthetic prokaryotes are emphasized.