This paper reports on topic-specific pedagogical content knowledge (PCK) enacted by three pre-service science teachers during their final year school-based internship. An interpretive, qualitative case study was conducted to investigate to what extent the pre-service teachers applied the knowledge taught during a preceding physical science method course, when teaching electromagnetism for the first time. The study is rooted in the revised consensus model of PCK with focus on the enacted PCK (ePCK) of pre-service teachers. Five topic-specific PCK components informed the design of an ePCK rubric used to assess the extent to which the pre-service teachers' PCK manifested in their practice. Data were captured by written content representations (CoRes), lesson observations and interviews. The rubric, together with further qualitative analysis, was used to determine how the pre-service teachers translated the knowledge taught during training into practice. Findings indicate that the participating pre-service teachers enacted certain components of the taught PCK and reasoned pedagogically about their teaching, though not at the same level for all main ideas in the topic. After teaching the topic, the pre-service teachers indicated that they would like to improve their sequencing of key concepts. It was concluded that the teaching experience contributed to a better understanding of conceptual teaching strategies. The findings of the study may inform PCK development in teacher education.