Table 1

Purification of GGH from the HT-1080 fibrosarcoma cell line

	Specific activity^1-a	Fold purification (cumulative)	Yield for individual step
	units/mg		%
Crude cytosol	0.002		100
Reactive Green 5 chromatography	0.77	386	72
Dialysis			83
Organomercurial agarose	3.6	1800	68
Sephacryl S-200^1-b	∼6.0	∼3003	21

↵1-a One unit is defined as the amount to convert 1 μmol of MTX glu₅ to lower polyglutamate forms (at 37°) in 1 min.
↵1-b Recoveries and GGH elution profile were dramatically affected by the presence or absence of thiols in applied sample and running buffer. The small quantities of protein available for total protein measurement made calculation of specific activities difficult.