Vitamin B12 deficiency alters the distribution of membrane proteins on linear sucrose gradients in the fruit bat brain.

Total particulate material prepared by homogenization in water and centrifugation at 100,000 g for 60 min from the brains of normal and vitamin B12-deficient fruit bats was fractionated on linear sucrose gradients (0.1 M-1.4 M sucrose). Animals were made vitamin B12-deficient by dietary deprivation or as a result of exposure to nitrous oxide. Based on absorbance at 280 nm three peaks were seen in material derived from the B12-deficient fruit bat brain and only two peaks in the normal animal. Myelin proteins were observed over a larger range of molarities of sucrose in the deficient brain than in the control tissue. Animals rendered vitamin B12-deficient by nitrous oxide treatment showed membrane protein patterns similar to those observed in the control animal.