Kinetic Characterization and Catalytic Mechanism of -Acetylornithine Aminotransferase Encoded by Gene from sp. PCC6803.

The enzyme encoded by gene from sp. PCC6803 was reported to function as -acetylornithine aminotransferase, γ-aminobutyric acid aminotransferase, and ornithine aminotransferase, which played important roles in multiple metabolic pathways. Among these functions, -acetylornithine aminotransferase catalyzes the reversible conversion of -acetylornithine to -acetylglutamate-5-semialdehyde with PLP as cofactor, which is a key step in the arginine biosynthesis pathway.

Kinetic and structural insights into enzymatic mechanism of succinic semialdehyde dehydrogenase from Cyanothece sp. ATCC51142.

As a ubiquitous enzyme, succinic semialdehyde dehydrogenase contributes significantly in many pathways including the tricarboxylic acid cycle and other metabolic processes such as detoxifying the accumulated succinic semialdehyde and surviving in nutrient-limiting conditions. Here the cce4228 gene encoding succinic semialdehyde dehydrogenase from Cyanothece sp. ATCC51142 was cloned and the homogenous recombinant cce4228 protein was obtained by Ni-NTA affinity chromatography.