Galactosamine inhibition of protein synthesis in Bacteroides thetaiotaomicron

Galactosamine does not support growth of Bacteroides thetaiotaomicron. Despite this, galactosamine was more effective than utilizable carbohydrates such as glucose in preventing synthesis of the inducible enzymes α-glucosidase and chondroitin lyase. Galactosamine also stopped overall protein synthesis. By contrast glucose and other utilizable carbohydrates increased the rate of protein synthesis. Addition of glucose to bacteria which had been treated with galactosamine restored the ability of the bacteria to synthesize protein and to produce inducible enzymes. Moreover, when B. thetaiotaomicron was incubated with [1-14C]galactosamine for 30 min at 37 °C, about one-third of the label which was taken up by the cells comigrated with glucosamine-6-phosphate on a thin-layer chromatogram. Thus galactosamine appears to be phosphorylated by the bacteria. After 2 h incubation of the bacteria with [1-14C]galactosamine, there was a significant increase in the amount of label which could be extracted from acidified e...