Cooperative nature of the binding of cholesterol on to synaptosomal plasma membranes of dog brain.

The 'binding' of cholesterol on to dog brain synaptosomal plasma membranes from aqueous cholesterol 'solutions' was studied. 'Binding' of exogenous cholesterol is a slow process, strictly depending on the concentration of cholesterol and the quantity of the membranes present. It appears that binding probably occurs in three distinct successive stages.

Non-enzymic interactions of nicotinamide adenine dinucleotide, of some of its synthetic analogues and other compounds with orthophosphate.

Changes in the ultraviolet (UV) absorption spectra of nicotinamide adenine dinucleotide (NAD), of its synthetic analogues, and of adenosine and its derivatives in the presence of high concentrations of orthophosphate were studied. The role of the carboxamide group of the nicotinamide moiety of NAD on these spectral changes was investigated by replacing that group with an acetyl or aldehyde group. The effect of the 6-amino group of the purine was investigated by studying the interaction of deamino-NAD and various adenosine derivatives with orthophosphate.