Glutarate semialdehyde dehydrogenase of Pseudomonas. Purification, properties, and relation to L-lysine catabolism.

Abstract

The lysine-induced glutarate semialdehyde dehydrogenase of Pseudomonas was purified to electrophoretic homogeneity from a mutant strain lacking delta-aminovalerate transaminase. The properties of the enzyme, including molecular weight, amino acid composition, electrophoretic behavior, and kinetic features, distinguish it from similar dehydrogenases induced in the same cell strain by hydroxyproline or by glucarate. Enzyme induction patterns and the growth behavior of a mutant deficient in glutarate semialdehyde dehydrogenase clearly relate this enzyme to the so-called delta-aminovalerate pathway of L-lysine catabolism. Induction studies also indicate that delta-aminovalerate is a better inducer of the dehydrogenase than L-lysine. Cells of a mutant strain lacking delta-aminovalerate transaminase contained higher levels of the dehydrogenase, presumably as a result of the accumulation of delta-aminovalerate, making this mutant a useful preparative source of the enzyme. The marked reduction of lysine-inducible glutarate semialdehyde dehydrogenase in a mutant strain permitted assessment of the basal levels of hydroxyproline/glucarate-inducible ketoglutarate semialdehyde dehydrogenases not possible in wild type cells.