[Properties of adenosine deaminase from cultured endothelial cells].

Cultivated calf aortic endothelial cells (line BZEz-7) show a remarkable activity of adenosine deaminase with a Vmax of 1.8 pmol/cell.min-1. The kM is about 160 mumol. The localization of the enzyme was determined intracellularly. The ADA is only of minor importance for the regulation of the adenosine uptake of endothelial cells. Their significance for the control of the immune system is discussed.