Date of Award:

5-1967

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Plants, Soils, and Climate

Department name when degree awarded

Plant Nutrition and Biochemistry

Committee Chair(s)

Gene W. Miller

Committee

Gene W. Miller

Committee

Harris O. Van Orden

Committee

Paul B. Carter

Committee

Lewis Jones

Abstract

The survey of plant species for aminolevalinic acid synthetase (ALAS) source was conducted. Under the conditions of this study, spinach leaves were found to be a good source of ALAS activity. The amount of amino levulinic acid (ALA) synthesized by the plant extracts was very small and was rapidly metabolized to porphyrins. ALA and porphyrin synthesis was found to be confined to the particulate fractions. Rupturing of the particles with ultrasonifier enhanced the penetration of succinyl-CoA and increased the activity. Direct study of the ALAS activity was enabled by the utilization of C14-compounds to the isolation by column chromatography.

Seven fold purification of the ALAS activity from spinach leaves was accomplished by the methods of differential centrifugation, sonification of the particulate fractions, ultracentrifugation, and phosphate-gel adsorption of the supernatant of ultracentrifugation.

The kinetic studies showed that 30 minutes incubation at 30° C would be optimum for the study. The reaction was very pH dependent and pH 7.0 was the optimum pH. Pyridoxal-phosphate and magnesium ion were required for optimum incorporation of succinyl-CoA and glycine into ALA. Iron activated ALAS in the cell free extract, and this shows conclusively that the effect of iron was directly on succinyl-CoA incorporation into ALA and not on permeability or fatty acid synthesis.

Download

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .