Allen, A. & Snary, D. (1972) Gut 13, 666-672 Florey, H. W. (1962) Gastroenterology 43, 326-329 Jencks, W. P. (1969) Catalysis in Chemistry and Enzymology, p. 393, McGraw-Hill , London Snary, D. & Allen, A. (1971) Biochem. J . 123, 845-853 Snary, D. & Allen, A. (1972) Biochem. J . 127, 577-587 Snary, D., Allen, A. & Pain, R. H. (1971) Eur. J . Biochem. 24, 183-189 Snary, D., Allen, A. & Pain, R....