Effects of the addition of sulphur compounds to the diet on utilisation of protein in young growing rats

Abstract A number of sulphur‐containing compounds were added to a 10% casein diet in order to indicate their ability to replace a supplement of methionine. Net protein utilisation (NPU) was determined. Cysteine, homocysteine and methionine hydroxy analogue produced as great an increase in NPU as did methionine. Methionine sulphoxide increased the NPU to a lesser extent. Methionine sulphoximine, methyl methionine sulphonium hydrogen sulphate and methionine sulphone caused reductions in NPU. Other organic and all inorganic sulphur compounds showed no methionine sparing action.