Interaction of aggregated catecholamines and nucleotides with intragranular proteins

Summary

Analytical ultracentrifugation at different sets of conditions in the temperature range between 10 and 34° C shows that mixtures of l-noradrenaline and adenosine-5′-triphosphate in the presence of Ca²⁺ always sediment jointly, i.e. with only one single schlieren peak together with intragranular expanded proteins obtained from bovine adrenal medulla. In contrast, two schlieren peaks are obtained on addition of a globular protein, such as serum albumin, to l-noradrenaline-Ca²-adenosine-5′-triphosphate mixtures. It is concluded that aggregates of l-noradrenaline and adenosine-5′-triphosphate interact with the expanded proteins present in the catecholamine storage organelles.