Adenoviruses are popular tools in today’s research, for example, for delivering therapeutics or as vectors for vaccinations. One important step to use adenoviruses for these purposes is mod-ifying the virus to suit one’s aim. A novel approach to modify the genome of adenoviruses is to use the AdenoBuilder system, which is based on a modular assembly where the whole ge-nome is divided into five separate plasmids and subsequently assembled and transfected to pro-duce new viruses. One interesting adenoviral protein is E1B19K. It is mainly known for its function of inhibiting apoptosis by sequestering Bak and Bax, which would otherwise form pores in the mitochondrial membrane, ultimately leading to apoptosis.This thesis used the AdenoBuilder to produce Myc-E1B19K encoding Human Adenovi-rus C5 . This virus contains a Myc epitope tag at the E1B19K protein, allowing efficient protein detection in different experimental settings. My data shows that Myc-E1B19K is located in the mitochondrial fraction after subcellular fractionation. Based on Bak and Bax elimination ex-periments, neither of these known interaction partners are responsible for delivering Myc-E1B19K to the mitochondria. Additionally, a Myc Microbead pulldown was performed to find interaction partners of Myc-E1B19K, which confirmed its mutual interaction with the Bak and Bax proteins. Finally, the Myc Microbeads were used to isolate ultrapure Myc-E1B19K-en-riched mitochondria, to establish a unique experimental system to study how E1B19K targets mitochondria.Ultimately, the generation of a new recombinant virus encoding Myc epitope-tagged E1B19K protein was successful, and the virus could be used for further analysis of E1B19K.