Date of Award
Doctor of Philosophy
A method for the extraction and quantitation of chloroplast pigments by high performance liquid chromatography (HPLC) was developed for several diverse fruits and vegetables. This method was much more effective than a previously published procedure for leaf pigments. HPLC in an isocratic mode of 1:1 (v/v) 80% methanol:ethyl acetate completely separated chlorophyll a and b and (beta)-carotene, while neoxanthin, violaxanthin and lutein eluted as partially resolved peaks with a run time of 25 minutes. A linear gradient of the two solvents resolved all six pigments in a run time of 48 minutes;Using the isocratic HPLC system, the chlorophyll a and b content was determined in developing 'Heinz 1350' tomato fruit in five day increments from 15 days past anthesis to fully ripe (55 days). When presented on a whole fruit basis, the data showed that the chlorophyll a and b contents increased from 15 days past anthesis to 35 days, and then decreased to zero at 55 days;In the same fashion, porphobilinogen deaminase activity was measured in extracts from the fruit, and several properties of the enzyme were determined. Results showed that changes in deaminase activity closely paralleled the changes in chlorophyll content with respect to fruit age. The data suggest that prophobilinogen deaminase activity may regulate chlorophyll biosynthesis in developing 'Heinz 1350' tomato fruit;The results of the characterizations of the enzyme showed that the tomato deaminase is similar to other deaminase enzymes isolated from leaf and animal sources.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Robert Waring McMahon
McMahon, Robert Waring, "Relationship of porphobilinogen deaminase activity to chlorophyll content and development of 'Heinz 1350' tomato fruit " (1984). Retrospective Theses and Dissertations. 9010.