By using a good substrate for ATP-dependent proteolysis, lysozyme, they found 1) that similar high-molecular weight derivatives were for med when I-labeled APF-1 was incubated with unlabeled lysozyme than whenI-labeled lysozyme was incubated with unlabeled APF-1. 2)analysis of the ratio of radiactivity in APF-1 and lysozyme dicated that the various derivatives consisted of increasing numbers f APF-1 molecules linked to one molecule of lysozyme 1234567 (Hershko et al, 1980 C C Courtesy of A Hershko. Used with permission of ne author Source: Figure 1 in Hershko et al. " Proposed role of ATP in protein breakdown: conjugation of protein with multiple chains of the polypeptide of ATP-dependent proteolysis. PNAS 1980 April 77(4):1783-1786• By using a good substrate for ATP-dependent proteolysis, lysozyme, they found: 1) that similar high-molecular weight derivatives were for med when 125 I-labeled APF-1 was incubated with unlabeled lysozyme than when 125 I-labeled lysozyme was incubated with unlabeled APF-1. 2) analysis of the ratio of radiactivity in APF-1 and lysozyme indicated that the various derivatives consisted of increasing numbers of APF-1 molecules linked to one molecule of lysozyme. (Hershko et al., 1980) Courtesy of A. Hershko. Used with permission of the author. Source: Figure 1 in Hershko et al. "Proposed role of ATP in protein breakdown: conjugation of protein with multiple chains of the polypeptide of ATP-dependent proteolysis." PNAS 1980 April; 77(4): 1783–1786