TABLE 1.

Summary of results from kinetic experiments on hNaa50p with various combinations of inhibitors and substrates (supplemental Figs. S1–S3)

Inhibitor and type of inhibition	Variable substrate	Fixed substrate (subsaturated)	Kinetic parametersa
Control	Acetyl-CoA (2–25 μm)	Peptide (300 μm)	Km = 5.0 ± 1.5 μm; Vmax = 6.0 ± 0.56b,c
CoA (0–80 μm), competitive	Acetyl-CoA (2–25 μm)	Peptide (80 μm)	KI = 2.27 ± 0.16 μm; Km = 4.7 ± 0.4 μm; Vmax = 5.7 ± 0.2b,c
Desulfo-CoA (0–60 μm), competitive	Acetyl-CoA (2–25 μm)	Peptide (80 μm)	KI = 67 ± 9 μm; Km = 17.4 ± 1.7 μm; Vmax = 21.2 ± 1.1b,c
CoA (0–80 μm), non-competitive	Peptide (30–500 μm)	Acetyl-CoA (100 μm)	KI = 27.7 ± 1.7 μm; Km 59 ± 5 μm; Vmax = 7.4 ± 0.3c,d

^a The kinetic parameters V_max and K_m are apparent values calculated for the experiments without added inhibitor. The specific activity of different lots of the purified enzyme may vary and thus contribute to variation in the values of these parameters.

^b Apparent K_m and V_max for acetyl-CoA in the absence of inhibitor.

^c V_max is given as picomoles of acetylated peptide × min⁻¹ × pmol hNaa50p⁻¹.

^d Apparent K_m and V_max for unacetylated peptide substrate.