The metabolic pathway of propionate in Euglena gracilis z grown under illumination.

Open Access
Publisher Website
Google Scholar
Abstract
Euglena gracilis grew with propionate as the sole carbon source under illumination but not in the dark. The metabolic pathway of propionate was determined in E. gracilis growing under illumination. Labeled propionate was first recovered in the amino acid fraction and gradually transferred to protein and paramylon with a lapse in incubation time. In the amino acid fraction aspartic acid was most densely labeled initially, followed by glutamic acid indicating that propionate is metabolized via succinate. The result agreed with the radiorespirometric pattern of specifically labeled propionates: 1-C>2-C=3-C. E. gracilis contained propionyl-CoA carboxylase, but not α-hydroxyglutarate synthase. The reaction product of the enzyme was identified as methylmalonyl-CoA. The enzyme activity increased in the log phase when propionate in growth medium was actively utilized for growth. From these results we have concluded that illuminated Euglena metabo-lizes propionate through propionyl-CoA and methylmalonyl-CoA to tricarboxylic acid cycle intermediates for growth.

This publication has 0 references indexed in Scilit: