Abstract: Background and Objective: Black komak seeds (Dolichos lablab) are a potential source of protein. Protein from seeds is thought to contain a protein fraction that is resistant to pepsin. The purpose of this study was to separate the protein fractions that are resistant to pepsin. Materials and Methods: The protein fraction was isolated from komak seed flour. Hydrolysis was performed in vitro; the protein isolates were hydrolyzed using pepsin at 37°C for 30 min in a water bath. A 0.05 M HCl solution was used as a buffer. The ratio between the protein and pepsin was 100:1. The solution was diluted to 5%. Proteins resistant to pepsin were separated and further fractionated into 7S and 11S protein fractions. Results: This study showed that pepsin could only hydrolyze some proteins. The amount of protein resistant to pepsin was 67.93 g/100 g. The 7S protein fraction was dominant compared with the 11S protein fraction. The ratio between the 7S protein fraction and the 11S protein fraction was 18.84: 1.00. Both fractions had different functional properties compared with their protein isolates. Fraction 7S consisted of 3 dominant bands with molecular weights of 41.21, 35.48 and 25.11 kDa. Fraction 11S consisted of 2 dominant bands with molecular weights of 35.48 and 28.18 kDa. Both fractions contained globulin proteins and their functional properties were different from the native protein fractions. Conclusion: This study found that pepsin can be used to separate the protein fraction that is dominated by globulins, specifically the 7S globulin fraction of protein. The 7S globulin fraction has the potential to be developed as a functional food ingredient.