Table 3.

Feedback regulation.

Compounds	DAH7PSAp activity remaining after treatment (%)a
None	100
L-Phenylalanine	93.9 ± 6.8
L-Tyrosine	88.9 ± 6.8
Chorismate	89.0 ± 6.7
Shikimate	99.9 ± 5.0
Prephenate	84.0 ± 2.5
L-Tryptophan	49.4 ± 3.9
L-Tryptophanb	41.8 ± 8.6

^aResults show the standard deviation of triplicate assays.

^badded after quenching with 10% TCA, but before the periodate-Aminoff thiobarbiturate assay.