tokens: Wild - type AT1A receptors , expressed in Chinese hamster ovary cells , rapidly internalized after Ang II stimulation [ t1 / 2 2 . 3 min ; maximal level of internalization ( Ymax ) 78 . 2 % ] , as did mutant receptors carrying single acidic substitutions ( T332E , t1 / 2 2 . 7 min , Ymax 76 . 3 % ; S335D , t1 / 2 2 . 4 min , Ymax 76 . 7 % ; T336E , t1 / 2 2 . 5 min , Ymax 78 . 2 % ; S338D , t1 / 2 2 . 6 min , Ymax 78 . 4 % ) .