Novel proteases, with excellent enzymatic properties, discovered from
pitcher fluid of Nepenthes × Miranda
Abstract
Pitcher fluid of Nepenthes × Miranda is usually discarded before
transportation despite containing many functional materials, in which
hydrolytic proteases are particularly attractive to us. In our study, we
collected the pitcher fluid of Nepenthes × Miranda and got pitcher fluid
proteases with 6.658 U/mL of proteolytic activity by concentration
treatment. Then the optimal pH and temperature were detected, and the
activators, denaturants and inhibitors were screened respectively.
Finally, Michaelis constants were calculated to quantify the affinity
with different substrates. The results showed that the highest activity
was at pH 2.05~2.50 and 50~55 ℃, which
indicated the advantages of lower pH and higher temperature compared
with the nepenthesins from other species of Nepenthes. Moreover, the
pitcher fluid proteases could be activated by Mn2+ significantly and
tolerated glycerol of high content. We discover a way of the new
protease resources, a rational use for biochemistry and a direction for
the reuse of agricultural waste.