XVI International Botanical Congess

'Moonlighting' proteins have more than one role in the cell and those roles may be apparently unrelated. We suggest that phosphoglycerate kinase (PGK), a 42kDa enzyme involved in glycolysis, gluconeogenesis and the Calvin cycle, is a moonlighting protein, its other role is as a primer-recognition protein (PRP) associated with DNA polymerase-alpha. Anti-PGK antibodies recognise an antigen in pea leaf nuclei as well as in cytosol and chloroplasts. The antibodies recognise PRP as a 42kDa polypeptide, pre-incubation of PRP with anti-PGK antibodies precipitates the PRP. In human cells PGK can substitute for PRP in DNA replication. Research is now aimed at understanding how the multiple roles are regulated.