One reference I have on hand: Galen et al. (1978) Biochem. Biophys. Acta, 523: 485-493. In article <4jc23i$s78 at falcon.le.ac.uk>, "Dr E. Buxbaum" <EB15 at le.ac.uk> wrote: > I think there was a publication on this in Anal. Biochem. some 2 or 3 > years back. Try the index.