Photosynthesis is a biologically important process in plants that takes place in chloroplasts. Even though it seems like a simple process which produces carbohydrates and oxygen from water and carbon dioxide, it is actually a series of light-driven oxidation-reduction reactions in which a large number of protein complexes take part. One of the most important protein complexes is photosystem II (PSII), where initiation of light-dependent photosynthetic reactions happens. The most important components of PSII are: antenna complex, the reaction center (made of D1 and D2 proteins) and oxygen evolving complex (OEC) which contains three small extrinsic protein subunits: PsbO, PsbP and PsbQ. In dark reactions (the Calvin cycle), organic molecules are formed from \( CO_{2} \) and the first step (\( CO_{2} \) fixation) is catalyzed by enzyme Rubisco. The aim of this work was to compare methods for determining the expression of photosynthetic proteins: D1, PsbO subunit of OEC and the large subunit of Rubisco. Proteins were isolated from the plant tissue using two methods: isolation of the total soluble proteins and isolation of proteins from chloroplasts. Isolated proteins were separated by molecular mass using electrophoresis (SDS-PAGE) and detected by Western blot method. Protein bands were detected on film using chemiluminescence. Comparison of protein bands obtained by two methods, the more suitable method for detection of photosynthetic proteins expression of was determined.