Other metabolite analogues of proven value in prophylaxis and therapy

4 Other metabolite analogues of proven value in prophylaxis and therapy 

Curiously enough, a metabolite analogue may be treated as a metabolite by one species and as an antagonist by a related species. For example, dethiobiotin 

Anti-metabolites are usually more effective in injuring those cells which require an external source of the metabolite, and pyrithiamine 9.5) provides an example (Woolley and White, 1943). Examples will now be given of antimetabolites which have become accepted as effective prophylactics or remedies. 

Amprolium 9.37), an analogue of thiamine (2.7), has proved highly successful in coccidiosis of poultry. This drug acts by inhibiting the transport of thiamine, in Eimeria, 50 times more strongly than in cells of the chicken gut (James, 1980). 

Sodium 2,2-dichloropropionate (dalapon, Dowpon ) is much used for killing grass in dicotyledonous crops such as beet and lucerne. Competitive studies in bacteria E. coli) point to its being an antagonist for the incorporation ofpantoic acid [i.e. the left-hand side of 9.38)] into pantothenic acid. This is the main site of its action on grasses its effect is diminished by external pantothenic acid Hilton et al., 1959). 

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