Table 2.

Amino acid composition of collagen subtype α chains ^a

Amino acid	α1(I)	α2(I)	α1(II)	α1(III)	α1(IV)	α2(IV)
Alanine	115	102	103	96	30	47
Arginine	50	50	50	46	22	42
Aspartic acid	42	44	43	42	45	49
Glutamic acid	73	68	89	71	78	65
Glycine	333	338	333	350	334	324
Cysteine	0	0	0	2	0	2
Histidine	3	12	2	6	6	6
Hydroxylysine	9	12	20	5	50	36
Hydroxyproline	109	94	99	125	123	111
Leucine	19	30	26	22	52	56
Lysine	26	18	15	30	6	7
Methionine	7	5	10	8	15	14
Phenylalanine	12	12	13	8	27	36
Proline	124	113	120	107	85	73
Serine	34	30	25	39	38	30
Threonine	16	19	23	13	19	30
Tyrosine	1	4	2	3	5	7
Valine	21	35	18	14	33	27

^aValues are number of amino acids per 1000 amino acids.³¹