Cobalamin (vitamin B 12 ) is an essential cofactor in a variety of enzymatic reactions and most prokaryotes contain transport systems to import vitamin B 12 . A gene coding for a periplasmic cobalamin‐binding protein of Photobacterium damselae subsp. piscicida was identified by in silico analysis of sequences from a genomic library. The open reading frame was composed of 834 bp encoding a protein of 277 amino acids. The protei...