Cytochrome P450s are the perfect choice for many biotechnological applications. The requirement for costly electron donors (NAD(P)H), redox partners, and uncoupling, the process of formation of reactive oxygen species instead of desired products, are limitations of P450s' extensive utilization. By selecting the best redox partners, and utilizing site-directed mutagenesis to improve protein-protein interaction, a novel P450 enzyme with increased activity can be obtained. Thermophilic CYP119 obtained from Sulfolobus acidocaldarius has a high potential as biocatalyst. In the current research, protein-protein interaction between electron transfer partner of P450cam, putidaredoxin (Pdx) and CYP119 was examined and their electron transfer efficiency was improved by rational design. Using PyRosetta Software, 14 mutants were created, using Rosie Docking Server, docking analysis were performed. The best models, N34E, D77R and N34E-D77R mutations were performed with site-directed mutagenesis method. Difference spectroscopy of substrate (lauric acid) binding to WT and mutant CYP119 revealed Kd values of 19 µM, 35 µM, 23 µM and 87 µM in WT CYP119, N34E, N34E-D77R and D77R mutant, respectively. The reported Kd for Pdx binding for WT is 2100 µM. Difference spectra of Pdx binding to WT CYP119 and mutants were followed to obtain dissociation constants. The observed Kd values for WT CYP119 and N34E, D77R, N34E-D77R mutants were 2390 µM, 112 µM, 797 µM and 200 µM, respectively. These outcomes offer solid evidence that the N34E, N34E-D77R mutants bind to Pdx with higher affinity, thus, showing an increase in electron-transfer rate for 21-fold in N34E and 12-fold N34E-D77R mutation in CYP119-Pdx-PdR system.