TABLE 2.

Effect of exogenous Hse on intracellular B₆ pool of the yggS mutant^a

Strain	pmol of indicated B6 vitamer/mg cells ± SD
	PLP		PNP		PMP
	No Hse	Hse	No Hse	Hse	No Hse	Hse
E. coli WTBW-pU0	14 ± 2	15 ± 1	0.3 ± 0.3	ND	24 ± 4	26 ± 3
E. coli ΔyggSBW-pU0	9.0 ± 2	17 ± 2	3.3 ± 0.2	8.0 ± 0.2	19 ± 2	29 ± 3

^aStrains WT_BW^-pU0 and ΔyggS_BW^-pU0 were grown in the M9 medium in the presence or absence of 1 mM Hse at 30°C. Log-phase cells were collected, and total intracellular B₆ vitamers were quantified as described in Materials and Methods. The yggS mutants accumulated PNP, and exogenous Hse further elevated the PNP level in the yggS mutant. Data represent means ± standard deviations of results from at least three independent experiments. ND, not detected.