Known luminous bacteria belong to the genera Vibrio, Photobacterium, Shewanella, and Photorhabdus. The enzyme luciferase catalyzing the luminous reaction is composed by the α and β polypeptides and subunit α is responsible for substrate binding and catalytic activities. Luciferases are classified into "slow " of Vibrio harveyi and "fast" of Photobacterium sps. on the basis of enzyme kinetics. Shewanella woodyi has "intermediate" kinetics. This research has tested the hypothesis of existence of three kinetic classes by sequencing luxA gene (coding for c subunit) of new strains and comparing these clusters to phenotypic analysis and sequencing of 16S rRNA. Phenotypic analysis has shown strains distinct from the known. LuxA amino acids and nucleotides and 16S rRNA sequences have shown 5 major lineages corresponding to known species. A dlade distinct from the known species was present. Geographic location and fish habitat didn't affect the distribution of strains.
