Furthermore, study of protein Epimedoside-A interactions using STRING database is crucial to understand the functional role of individual proteins in a well-organized biological network. Here we have used recent bioinformatics tools to assign function to all HPs encoded by H. influenzae genome. The Receiver Operating Characteristic analysis is used for evaluating the performance of used bioinformatics tools. We also measured the confidence level of the function prediction on the basis of used bioinformatics tools. The function prediction has high confidence level if more than three tools indicate the same functions. While if there is less than three tools then it is less confidently predicted function. So, we have successfully assigned functions to all 296 HPs of H. influenzae genome with high confidence. We have performed an extensive sequence analysis of proteins associated with virulence using tools like Virulentpred and VICMpred, because H. influenzae is the causative agent of infection in respiratory tract. We identified 14 oxidoreductase enzymes, which are critically important for bacterial virulence and pathogenesis. It is well understood that the disulfide bonds are important for the stability and/or structural rigidity of many extracellular proteins, including bacterial virulence factors. Bond formation is catalyzed by thioldisulfide oxidoreductases. Oxidoreductases like SdbA is required for disulfide bond formation in S. gordonii, which is required for autolytic activity. Protein P45154 contain Estradiol Benzoate 2Fe-2S ferredoxin-type domain. Many bacteria produce protein antibiotics known as bacteriocins to kill competing strains of the same or closely related bacterial species. We identified protein P44743 as a radical SAM protein, it is understood that radical SAM proteins play a significant role in pathogenesis of an organism and is also validated that the inhibition of these enzymes is effective in preventing the lethal diseases. Similarly, we identified 39 transferase enzymes which are required for the efficient spore germination and full virulence of bacteria like Bacillus anthracis. Transferase enzymes are essential for biosynthesis of lipoprotein, and bacterial lipoproteins play an important role in virulence of bacteria. Proteins Q57022, P44064 and P45180 are glycosyl transferase, and on mutation it affects extracellular polysaccharide and lipopolysaccharide biosynthesis, cell motility, and reduces the development of disease symptoms. We have characterized protein P44256 as DNA polymerase IV and it is observed that virulent strains contain increased level of activity of DNA polymerase than nonvirulent strains, indicating its role in virulence. The protein Q57544 is found to be a b-lactamase. The enzyme responsible for generation of resistance against b-Lactam antibiotics like penicillin, cephalosporins, etc.. We annotated 56 hydrolase enzymes having an established role in virulence of bacteria, e.g. Kdo hydrolase is the main cause of virulence in Francisella tularensis, which is classified as a bioterrorism agent. Similarly, nudix hydrolase encoded by nudA gene in Bacillus anthracis is important for the complete virulence. There are 8 lyase enzymes. These are important for the virulence of pathogen in host. The P44717 protein is a cystathionine b-lyase, an enzyme which forms the cystathionine intermediate in cysteine biosynthesis, may be considered as the target for pyridiamine anti-microbial agents. Similarly, isocitrate lyase is an enzyme of glyoxylate cycle, which catalyzes the cleavage of isocitrate to succinate and glyoxylate together with malate synthase. This enzyme bypasses two decarboxylation steps of TCA cycle.