Table 2.

Molecular mass data of hybrid pools of human ASL at 25 °C and pH 7.0

Enzyme	Molecular mass by AUCa (kDa)
	M-Tet	D-Tet
His-tag WT	58 ± 1 (23%)
	228 ± 0.5 (77%)
His-tag R194C	57 ± 1 (27%)
	229 ± 2 (73%)
His-tag L311V	57 ± 0.5 (32%)
	230 ± 1 (68%)
His-tag R396H		116 ± 1(20%)
		227 ± 2(80%)
His-tag R396C	56 ± 2 (22%)
	227 ± 1 (78%)
non-His-tag WT/His-tag WT
Pool 1	55 ± 0.8(32%)
	219 ± 1 (68%)
Pool 2b	56 ± 3 (27%)
	223 ± 2 (73%)
Pool 3b	55 ± 2 (25%)
	230 ± 2 (75%)
non-His-tag 396C/His-tag WT
Pool 1	55 ± 1 (24%)
	218 ± 2 (76%)
Pool 2	56 ± 0.6 (27%)
	222 ± 1 (72%)
Pool 3c	57 ± 1 (30%)
	227 ± 3 (70%)
non-His-tag R396H/His-tag WT
Pool 1	54 ± 1 (25%)
	221 ± 2 (75%)
Pool 2d	58 ± 1 (27%)
	225 ± 2 (73%)
Pool 3	57 ± 1 (28%)
	229 ± 2 (72%)
non-His-tag R396C/His-tag R194C
Pool 1	54 ± 1 (20%)
	217 ± 3 (80%)
Pool 2e	57 ± 2 (22%)
	223 ± 3 (78%)
Pool 3e	56 ± 2 (20%)
	227 ± 2 (80%)
non-His-tag R396H/His-tag L311V
Pool 1	55 ± 0.5 (26%)
	220 ± 2 (74%)
Pool 2f	57 ± 2 (26%)
	224 ± 2 (74%)
Pool 3f	58 ± 3 (26%)
	229 ± 2 (74%)

^aThe molecular mass by AUC was measured at 25 °C, using ~0.1 mg/ml sample in fresh Enzyme Storage Buffer, pH 7.0, at 11,000 rpm. The experiments were performed within 48 hrs after eluting all the pools. M = monomer, D = dimer, Tri = trimer, Tet = tetramer, and the dash (−) is used to indicate that different species are in equilibrium. The percentage of each species is given in parenthesis. The AUC data of the following pools are fit equally well to the following models:

^bpools 2 and 3 of non-His-tag WT/His-tag WT also fit to D-Tet (27%,73%) model,

^cpool 3 of non-His-tag R396C/His-tag WT also fits to M-Tri (30%,70%) model,

^dpool 2 of non-His-tag R396H/His-tag WT also fits to M-5mer (29%, 71%) model,

^ein non-His-tag R396C/His-tag R194C pair, pool 2 also fits to M-5mer (25%,75%) model, while pool 3 also fits to the M-Tri (18%,82%) model, and

^fpool 2 and 3 of non-His-tag R396H/His-tag L311V also fits to M-5mer (30%, 70%) model.