Plasmids for expression of human superoxide dismutase (sod) analogs

Abstract

An improved plasmid for the production of superoxide dismutase which upon introduction into a host containing the thermolabile repressor C.sub.I renders the host capable of effecting expression of a gene encoding superoxide dismutase. The plasmid includes in 5' to 3' order the following: the promoter and operator P.sub.L O.sub.L from lambda bacteriophage; the N utilization site; a first restriction enzyme site permitting replacement of the ribosomal binding site which follows thereafter; a ribosomal binding site; an ATG initiation codon; a second restriction enzyme site; a gene encoding superoxide dismutase; an origin of replication and a gene associated with a selectable or identifiable phenotypic trait manifested when the plasmid is present in the host. The distance between the 3' end of P.sub.L O.sub.L and the 5' end of the N utilization site is less than about 80 base pairs. The distance between the 3' end of the N utilization site and the 5' end of the ribosomal binding site is less than about 300 base pairs. Host vector systems have been constructed from these plasmids and used to produce human superoxide dismutase and analogs thereof. Such SOD or analogs may be used to catalyze the reduction of superoxide radicals, reduce reperfusion injury, prolong the survival time of isolated organs and reduce spinal cord injury.