The cytidine diphosphate choline content of rat brain.

phosphorylase is responsible for the initial stages of maltose metabolism by these lactobacilli. Presumably, the s-glucose 1-phosphate produced is metabolized by the cells, but this work gives little indication of its subsequent transformation. The infrared spectra of the preparations of bacterial ,8-glucose 1-phosphate indicate that they are free from the a-anomer, which might be expected as a contaminant if the next step in the transformation led to the production of a-glucose 1-phosphate. The maltophosphorylase mechanism appears to be prodigal of carbohydrate, in that a molecule of glucose is rejected for every molecule of maltose utilized. However, it carries with it the biological advantage of sparing ATP, in that a molecule of phosphorylated glucose is produced without expenditure of ATP. It is perhaps noteworthy that the natural habitat of these lactobacilli (beer and brewer's malt wort) contains maltose as the predominant sugar, so that the maltophosphorylase system may have been elaborated by them in response to prolonged culture in the presence of maltose.