Table 3.

Modification sites identified in human lens αA and αB

Subunit	Modification	Residue	References
αA	Oxidation	Met1 Trp9 Met138 Tyr18 Tyr34 His154	[21–23, 30, 98, 99] [30, 98, 99] [21–24] [24] [24] [99]
	Disulphide bond	Cys131–Cys142	[21, 22]
	Deamidation	Gln6 Gln50 Gln90 Asn101 Gln104 Asn123 Gln126 Gln147	[21–23, 30] [22, 23] [21, 22, 26, 30] [22, 23] [21, 26] [23, 26, 30] [23, 26] [21, 22, 26, 30]
	Truncation	Met1–Gln50 Glu102–Ser173 Ser173 Met1–Arg65 Met1–Phe80 Ala152–Ser173 Ser169–Ser173	[22] [22] [22] [21] [21] [22] [22]
	Acetylation	Met1 Lys70 Lys78 Lys88 Lys145	[23, 99] [24, 100, 101] [24] [24] [24]
	Carboxymethylation	Lys11	[23]
	Carboxyethylation	Lys11	[23]
	Carbamylation	Lys99	[23]
	Methylation	His79 His154 Arg21 Lys88 Val89 Gln90 Ile146 Gln147 His154 Arg157	[99] [23] [24] [24] [99] [99] [99] [99] [99] [99]
	Ethylation	Thr13 His79 Val89 Ile146	[99] [99] [99] [99]
	Formylation	His79	[98]
	Conversion to DHA	Ser59	[98]
	dkpD formation	Asp67	[102]
αB	Oxidation	Met1 Trp9 Trp60 Met68 Tyr48	[21–23, 25, 99, 103] [23, 99] [24, 99] [21–25, 99, 103] [24]
	Deamidation	Gln26 Asn78 Gln108 Asn146	[23, 26] [21, 26] [21, 22, 26, 104] [23, 26, 30, 99]
	Carboxymethylation	Lys82 Lys90 Lys92 Lys103 Lys174	[23] [23] [23] [23] [23]
	Carboxyethylation	Lys92 Lys175	[23] [23]
	Acetylation	Met1 Lys92	[23, 99, 103, 105] [24, 106]
	Methylation	His83 Arg22 Arg50	[23, 99] [24] [24]
	Ethylation	His8 Val93 Gln108	[99] [99] [99]
	Carbamylation	Met1 Glu164 Lys166 Lys92 Lys175	[99] [99] [23] [99, 106] [101]
	Truncation	Met1–Pro46 Gln151–Lys175 Val152–Lys175 Ser153–Lys175 Gly154–Lys175 Pro155–Lys175 Arg163–Lys175 Glu164–Lys175 Ala171–Lys175 Ala172–Lys175 Lys175 Pro130–Lys175 Met1–His7	[105] [103] [103] [103] [103] [103] [103] [103] [103] [25] [22, 103, 105] [104] [22]