pseudomonas aeruginosa exoenzyme s has appeared to be relatively indiscriminate in its choice of substrates , but in fact it adp-ribosylates only a small subset of cellular proteins and exhibits a marked preference for several different membrane-associated proteins of apparent mr = 23,000-25,000 , at least some of which appear to bind gtp .
C0033684
proteins
C0025252
membrane-associated proteins