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The effect of δ-aminolevulinc acid (ALA) biosynthetic precursors and related compounds on the ALA productivity from a strain of Rhodobacter sphaeroides has been examined in vivo and in vitro systems. The relative ratios of ALA productivities by Capathway to that by C_5-pathway in vivo and in vitro systems were 0.78 and 1.37, respectively. Although the expression rates of C₄- and C_5-pathways in cell-free systems prepared after precursors supplemented cultivations were increased 1.35 and 1.52 folds, respectively, the rate increase of C₄-pathway was accompanied by the rate decrease of the C_5-pathway, and vice versa, as that the rates of both C₄- and C_5-pathways were lowered to be 0.91, 0.83, respectively. The order of cellular uptake rates of γ-glutamyl derivatives relative to that found with L-glutamic acid were shown to be D-glutamic acid, 0.55: D-glutamine, 0.5: L-glutamine, 0.4: γ-L-glutamyl ethylester, 0.3: GSH and Glu-pNA, 0. L and D configurations of glutamine were indicated as better substrates in vivo for ALA yields than those of glutamic acid, respectively.
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