TABLE 2.

Activities of the arginine succinyltransferase pathway enzyme and NAD synthetase in the wild type and an nit strain

Strain	Sp act ofa:
	AstB	AstC	AstE	NAD synthetase
TA1650 (wild type)	2.0 ± 0.21	42 ± 3.5	3.3 ± 0.34	22 ± 2.9
SK51 (nit-12)	2.2 ± 0.24	40 ± 3.2	5.3 ± 0.45	<3

^aAll units are in nanomoles per minute per milligram of protein. The values are the averages of three determinations ± standard errors of the means. Cells for the assays for AstB, AstC, and AstE were grown in minimal medium with 0.4% glucose as the carbon source and 0.2% alanine as the nitrogen source. Of the media that supported growth of SK51, this medium gave the highest levels of arginine succinyltransferase enzymes. Cell growth, extract preparation, and assays for AstB (succinylarginine dihydrolase), AstC (succinylornithine transaminase), and AstE (succinylglutamate desuccinylase) have been described previously (6). Cells for the NAD synthetase assay were grown in minimal medium with 0.4% glucose and 0.2% (NH₄)₂SO₄ at 30°C. Extracts were prepared as described for the other assays, except that the concentration of the phosphate buffer was 10 mM, instead of 50 mM. The assay for NAD synthetase has been described previously (8).