Purine nucleoside phosphorylase in lymphocytes of various mammalian species.

The distribution of purine nucleoside phosphorylase has been assessed by light and electron microscopy in peripheral lymphocytes of man, the rabbit, rat, mouse, guinea-pig, pig and dog. The enzyme activity was detected in the cytosol of the majority of lymphocytes in all species. The amount of reaction product was high in the rabbit, man, guinea-pig and dog, mpderate in the rat and very low in the pig and mouse. Other blood cell types are reactive as well, although there is a variation between species. A possible relationship of purine nucleoside phosphorylase with particular subpopulations of lymphocytes is suggested.