Plasmid MIP233, the unique member of the IncHI3 subgroup of the H incompatibility complex, is a large self-transferable plasmid encoding for sucrose utilization, the PacB character and resistance to tellurite. The current study examined whether pMIP233 conferred other putatively advantageous plasmid-encoded functions. Heavy metal studies revealed pMIP233 phenotypes of resistance to cadmium, cobalt, lead, zinc and nickel. Sequencing of random clones from a pMIP233 library revealed extensive homology with IS elements and genes involved in the metabolic processes demonstrated. Interestingly, pMIP233 did not appear to code for resistance to a wide range of antibiotics. pMIP233 is considered to be a metabolic plasmid.