Table 1. Nucleophilic Functional Groups in LDL.
residue | total | reactive |
---|---|---|
lysine ϵ-NH2 | 350 | 225a |
EPs | 80 | 80 |
histidine | 115 | 115 (maximum) |
cysteine | 25 | 25 (maximum) |
total | 570 | 445 |
TNBS reactive amino groups are 317 ± 29 and include all “reactive” (toward both TNBS and formaldehyde) lysines and all EPs or approximately 225 + 80 = 305. Maximum possible values are indicated since the number of “reactive” histidine and cysteine residues is unknown (41).