TABLE 1.

Amino acid analysis of human four-protein complex

The experimental amino acid composition of purified complex, as determined via amino acid analysis, is compared with three expected compositions based on the three potential FXN^42–210/ISCU/NFS1/ISD11 molar ratios shown. For each molar ratio, the variation between the experimental and expected number of each amino acid and the total % variation is shown. Sixteen amino acids were quantified; tryptophan and cysteine are degraded by the hydrolysis process, and asparagine and glutamine are detected as aspartic and glutamic acid, respectively (75).

Amino Acid	Experimental composition (no. of amino acids)	FXN-ISCU-NFS1-ISD11 (1:1:1:1)		FXN-ISCU-NFS1-ISD11 (1:1:2:1)		FXN-ISCU-NFS1-ISD11 (1:1:1:2)
		Expected composition (no. of amino acids)	Variation	Expected composition (no. of amino acids)	Variation	Expected composition (no. of amino acids)	Variation
Ala	70.8	63	−7.8	93	22.2	69	−1.8
Arg	51.0	49	−2.0	76	25.0	62	11.0
Asp	78.9	72	−6.9	102	23.1	82	3.1
Glu	96.8	85	−11.8	131	34.2	93	−3.8
Gly	62.3	60	−2.3	92	29.7	62	−0.3
His	25.8	28	2.2	47	21.2	29	3.2
Ile	44.6	46	1.4	76	31.4	52	7.4
Leu	75.7	76	0.3	111	35.3	83	7.3
Lys	55.1	61	5.9	82	26.9	67	11.9
Met	21.6	24	2.4	39	17.4	27	5.4
Phe	18.3	17	−1.3	24	5.7	19	0.7
Pro	30.4	35	4.6	55	24.6	37	6.6
Ser	60.9	67	6.1	104	43.1	71	10.1
Thr	46.6	45	−1.6	65	18.4	49	2.4
Tyr	29.7	30	0.3	45	15.3	35	5.3
Val	58.5	59	0.5	91	32.5	66	7.5
Total amino acids	827.2	817	−10.2	1233	405.8	903	75.8
Total percent variation			1.20%		32.90%		8.40%