Determination of esterase activity of SABP2 using fluorescence spectroscopy

BIOL 34

Laude Bannerman-Akwei, zlbb26@imail.etsu.edu, Department of Chemistry, East Tennessee State University, Box 70695, Johnson City, TN 37614, Dhirendra Kumar, Department of Biological Sciences, East Tennessee State University, Box 70703, Johnson City, TN 37614, and Yu Lin Jiang, jiangy@etsu.edu, Chemistry, East Tennessee State University, Box 70695, Johnson City, TN 37614.
Currently, plant diseases are still a major threat in developed and underdeveloped countries. A plant protein SABP2 was found to be essential in plant immune systems to control plant diseases, such as the cassava mosaic virus. This is because the corresponding protein SABP2 will generate a plant hormone, salicylic acid (SA), as an alert signal, through the hydrolysis of a volatile and cell permeable methyl salicylate (MeSA). The SA will then induce programmed cell death of part of the plant for the benefit for the rest. To test how MeSA is hydrolyzed to SA, currently, tritium radioactivity is applied to measure the activity of the enzyme SABP2; however, the operation is cumbersome. Thus, a convenient assay was developed to determine the activity of SABP2 towards a series of synthesized methyl esters of substituted salicylic acids by using fluorescence. For instance, it was found that the fluorescent intensity at 406 nm increased by ~86-fold when MeSA was hydrolyzed to SA. The steady-state kinetic data for the hydrolysis were also obtained using the SA's continuous fluorescence assay.
 

Frontiers in Chemical Biology
5:00 PM-7:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Biological Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007