A primary isotope effect was utilised in an in vitro study to allow the isolation and characterisation of an intermediate between proclavaminic acid and clavaminic acid, in clavulanic acid biosynthesis.1 1 For preliminary details see J. E. Baldwin, R. M. Adlington, J. S. Bryans, A. O. Bringhen, J. B. Coates, N. P. Crouch, M. D. Lloyd, C. J. Schofield. S. W. Elson, K. H. Baggaley, R. Cassells, and N. H. Nicholson, J. Chem. Soc. Chem. Commun., 1990, 617. © 1991.
