TABLE 3.

Inhibition constants for lysine and the analogs in Fig. 1 in the TilS reaction

No.	Compound	IC50	R1	R2	X	R30	R4
		μm
1	Lysinea	0.68 ± 0.04			CH2	H
2	Aminoethylcysteine	0.045 ± 0.003			S	H
3	Aminoethylserine	0.40 ± 0.02			O	H
4	(5R)-5-Hydroxylysine	17.6 ± 0.8			CH2	OH
5	Lysinamide	620 ± 70		CONH2	CH2	H
6	Cadaverine	910 ± 40		H	CH2	H
7	N-α-methyl-lysineb	1300 ± 120			CH2	H
8	6-Aminohexanoic acid	>1000	-H		CH2	H
9	Norleucine	>1000			CH2	H	H
10	4,5-trans-Dehydrolysine	2.5 ± 0.1
11	Ornithineb	700 ± 150
12	Arginine	>1000
13	N-Acetylethylenediamine	6.8 ± 0.9
14	Histamine	330 ± 20
15	Ethanolamine	1770 ± 150
16	Glycine	>1000
17	β-Alanine	>1000

^aThe apparent inhibition by lysine is the consequence of isotopic dilution of the radiolabeled substrate.

^bAs described in the “Results,” these samples apparently contained contaminating lysine.