In this qualitative case study, we examined the nature of integration among pedagogical content knowledge (PCK) components. To attain the goal, two experienced chemistry teachers' teaching redox reactions and electrochemical cells was observed. The data were collected through card-sorting activity, content representation (CoRe) tool, observation, and interviews. The data analysis included three steps, namely; in-depth analysis, enumerative approach, and constant-comparative methods. Results reveal that knowledge of learner and instructional strategy components were central in the integrations. However, knowledge of assessment and curriculum were less effective in shaping teachers' teaching. Additionally, the integrations were specific to topic taught. More coherent integration was observed in both teachers' teaching electrochemical cells topic. With the quantification of PCK integration, this study provides an opportunity to discriminate integrations regarding their type, quality, and strength. Implications for both pre- and in-service teacher education programs were suggested.