TABLE 4.

TSase α and β₂ activities of trpA prfA1(Ts) strains^a

Strain	Characteristics	Sp act ofb:		TSase α/ TSase β2c
		TSase α	TSase β
VK800	tnaC-UAG-tnaA′-′lacZ	2.8	3.3	0.85
VK801	VK800 prfA1	3.4	4.9	0.69
VK805d	VK801 trpA9761	0.17e	15	0.01
VK805d	VK801 trpA9761	0.07e	13	0.01

^aCultures were grown overnight in minimal medium (49) supplemented with 0.2% glycerol, 0.05% acid-hydrolyzed casein, and 4 μg indole per ml. For TSase assay conditions, see Materials and Methods. 

^bIndole plus serine to tryptophan reaction. 

^cRatio of specific activities of TSase α and TSase β₂. 

^dTwo different VK805 isolates were used. 

^eCorrected for the inherent activity of TSase β₂ in the indole to tryptophan reaction.