Intracellular 5-Phosphoribosyl-1-Pyrophosphate: Decreased Availability During Glutamine Limitation

Cholera toxin coupled to peroxidase yielded a highly specific ultrastructural marker of plasma membrane monosialogangliosides. Studies with cultures of brain and brain tumors suggested that long-term culture of tissue in monolayers results in eventual loss of surface monosialogangliosides.