Characterization of functional proteases from flowers of tea (Camellia sinensis) plants

Recently, functional compounds of flowers of tea (Camellia sinensis) have attracted increasing interest of researchers, whereas very less attention has been paid to functional enzymes in tea flowers. In the present study, tea flowers were found to contain proteases with strong proteolysis ability towards proteins from tea leaves. The crude proteases from tea flowers increased by 177% of total amino acids of tea infusion (protein:tea infusion, 1:3000), which was much higher than those of commercial proteases. LC-MS/MS analysis and protease inhibition experiments indicated that serine carboxypeptidase-like protein (SCLP) was one of major proteases in tea flowers. Recombinant CsSCLP was responsible for improvement of amino acids of tea infusion and CsSCLP was equivalently expressed in floral stages and most floral tissues. This study provides evidence of occurrences of proteases in tea flowers for the first time and an effective approach to improve contents of amino acids of tea infusion.