TABLE 3.

Effects of glutamate, ammonium chloride, glucose, and/or potassium phosphate buffer on GS activity in SA mixture^a

Expt no. and additive(s)	mM additive	Relative activity (%)
1, glutamate and ammonium chlorideb	50, 50	91
	100, 100	113
	200, 200	104
	300, 300	93
	400, 400	97
	50, 400	88
	400, 25	103
2, glucose	50	107
	100	104
	150	100
	200	90
3, phosphate buffer	50	72
	100	48
	150	33

^aVarious concentrations of glutamate, ammonium chloride, and/or potassium phosphate buffer (pH 7.0) were added to SP mixture. GS activity is indicated relative to activity without the additive. 

^bThe two values are respective.