Table 2.
Suspected modification sites found on various samples of in vitro glycated HSA
| Digest | Residues | Relevant Amino Acid | Suspected Modification Sitesa | |
|---|---|---|---|---|
| HSA-2 | Trypsin | 1–10 | N+, K4, R10 | N+ (FL-1H2O) + K4 (AFGP) |
| Trypsin | 275–286 | K276, K281, K286 | K276 & K281 (FL & FL-1H2O) | |
| Trypsin | 539–557 or 542–560 | K541, K545, K557 K545, K557, K560 |
K545 & K557 (FL-2H2O & FL-2H2O) or (FL-1H2O & Pyr) K545 & K557 (FL-2H2O & Pyr) or (FL + CEL) |
|
| Glu-C | 278–292 | K281, K286 | K281 & K286 (FL & CEL) or (FL-2H2O & Pyr) | |
| Glu-C | 83–100 | K93, R98 | K93 (FL-2H2O) or K93 & R98 (CEL & MG-H1) | |
| Glu-C | 566–585 or 168–188 | K573, K574 K174, K181, R186 |
K573 and K574 (AFGP*2) K174 & R186 (FL & ArgP) |
|
| Lys-C | 196–205 | K199, K205, R197 | K199 & R197 (FL & 3-DG-H1/THP) | |
| Lys-C | 414–432 | K414, K432, R428 | K414 & R428 (FL-1H2O & AFGP) or K414 & R428 (AFGP and 3-DG-H1/THP) | |
| HSA-5 | Trypsin | 520–525 | K524, K525, R251 | R521 & K524 (Pyr & G-H1) |
| Trypsin | 275–286 | K276, K281, K286 | K276 & K281 (FL & FL-1H2O) | |
| Glu-C | 281–294 | K281, K286 | K281 & K286 (FL-2H2O & CEL) | |
| Glu-C | 426–442 | K432, K436, K439, R428 | R428 & K439 (G-H1 & Pyr) and (ArgP & CEL) | |
| Glu-C | 189–208 | K190, K195, K199, K205, R197 | K199 & R197 (Pyr & IB) | |
| Lys-C | 5–20 | K12, K20, R10 | K12 (FL) | |
| Lys-C | 414–432 | K414, K432, R428 | K414 & R428 (FL-1H2O & AFGP) or (AFGP & 3-DG-H1/THP) | |
| Lys-C | 525–534 | K525, K534 | K525 (FL-1H2O) | |
| HSA-4 | Trypsin | 1–12 | N+, K4, K12, R10 | N+ & K4 (CEL & FL-2H2O) or N+ & R10 (FL-1H2O & MG-H1) |
| Trypsin | or 200–212 or 403–413 |
K205, K212, R209 K413, R410 |
K205 & R209 (CML & ArgP) K413 or R410 (AFGP) |
|
| Trypsin | 198–209 or 182–195 or 206–218 |
K199, K205, R209 K190, K195, R186 K212, R209, R218 |
K199 & K205 AFGP, (FL & Pyr), or (FL-1H2O+FL-2H2O) R186 & K190 (ArgP & Pyr) R209 & K218 (FL-1H2O & MG-H1) |
|
| Trypsin | 258–274 | K262, K274 | K262 (FL-1H2O) | |
| Glu-C | 312–321 | K313, K317 | K313 & K317 (AFGP & AFGP) | |
| Glu-C | 557–571 | K557, K560, K564 | K560 & K564 (FL & CML) | |
| Glu-C | 426–442 | K432, K436, K439, R428 | K439 (FL) or R428 & K439 (Pyr+MG-H1) | |
| Glu-C | 83–100 | K93, R98 | K93 (FL-2H2O) or K93 (CEL) & R98 (MG-H1) | |
| Glu-C | 189–208 | K190, K195, K199, K205, R197 | K199 & R197 (Pyr & IB) | |
a
The most likely modification sites, which were identified based on computational and structural data, are given in bold. The abbreviations for the types of glycation are defined in Table 1.