|Grohmann, Karl - RETIRED USDA|
Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 28, 2003
Publication Date: July 20, 2003
Citation: CAMERON, R.G., SAVARY, B.J., HOTCHKISS, A.T., FISHMAN, M.L., CHAU, H.K., GROHMANN, K. ISOLATION, CHARACTERIZATION AND PECTIN MODIFYING PROPERTIES OF A THERMALLY TOLERANT PECTIN METHYLESTERASE FROM CITRUS SINENSIS VAR. VALENCIA. AMERICAN SOCIETY OF PLANT BIOLOGISTS ANNUAL MEETING. 2003. AMERICAN SOCIETY OF PLANT BIOLOGISTS. PAPER NO. 253. Technical Abstract: The third, of four, chromatographic forms of pectin methylesterase (PME) from Citrus sinensis fruit tissue has been isolated and characterized. This PME is apparently glycosylated as it binds to Concanavalin A, which is consistent with reports of the thermally tolerant PME from grapefruit finisher pulp and orange juice extracted from two sweet orange varieties with a commercial juice extractor. This PME demonstrates biochemical characteristics that differ from two previously isolated forms. It has an apparent molecular weight of approximately 37 kDa and an isoelectric point between 9 and 10. It is active in the absence of cations and shows a broad peak of activity between 50 and 300 mM NaCl. Its pH optimum is salt dependent, requiring higher salt concentrations at lower pHs. At pH values greater than 6.5 the salt dependency is eliminated.