TABLE 4.

Effects of Ydj1 mutants on Hap1-18 activity^a

Heme level	β-Galactosidase activity (Miller units) in presence of Ydj1 or Ydj1 mutant
	Ydj1	Vector	F47L	N104	N134	N172	N206	N274	N363	G315E
Low	2.2 ± 0.6	124 ± 6	39 ± 4	24 ± 1.5	18 ± 1	2.6 ± 0.4	2.4 ± 0.3	3.5 ± 0.6	5.3 ± 0.5	5.3 ± 1.2
High	1,240 ± 257	1,531 ± 281	1,491 ± 237	1,351 ± 122	1,054 ± 24	1,060 ± 34	885 ± 150	1,254 ± 157	1,066 ± 136	990 ± 56

^aYeast Δydj1 Δhem1 cells expressing Hap1-18 and bearing the expression plasmid for wild-type Ydj1, the indicated mutants, or the empty vector and a Hap1-driven reporter were grown in the presence of a low (2.5 μg/ml) or high (250 μg/ml) level of heme precursor ALA. β-Galactosidase activities were detected, and data shown are averages (± standard deviations) of at least three independent transformants.