Table 1.
The mass of semi-carbazide-conjugated peptide fragments in semi-carbazide-modified cardiotoxin 1 (SEM-CTX1) and SEM-CTX3.
| Tryptic Peptides | Positions (#) | Predicted Mass (Da) | Measured Mass (Da) |
|---|---|---|---|
| CTX1 | |||
| MFMMSDLTIPVKR | 24–36 (Asp29) | 1569 | 1569.1 |
| GC(a)IDVC(a)PK | 37–44 (Asp40) | 950 | 948.6 |
| YVC(a)C(a)NTDR | 51–58 (Asp57) | 1089 | 1087.6 |
| SEM-CTX1 | |||
| MFMMSD(b)LTIPVKR | 24–36 (Asp29) | 1626 | 1626.6 |
| GC(a)ID(b)VC(a)PK | 37–44 (Asp40) | 1007 | 1005.6 |
| YVC(a)C(a)NTD(b)R | 51–58 (Asp57) | 1146 | 1144.7 |
| CTX3 | |||
| GC(a)IDVC(a)PK | 37–44 (Asp40) | 950 | 948.6 |
| YVC(a)C(a)NTDR | 51–58 (Asp57) | 1089 | 1087.6 |
| SEM-CTX3 | |||
| GC(a)ID(b)VC(a)PK | 37–44 (Asp40) | 1007 | 1005.6 |
| YVC(a)C(a)NTD(b)R | 51–58 (Asp57) | 1146 | 1144.7 |
(a) The sulfhydryl group of the cysteine residue is conjugated with -CH2-CONH2. (b) The carboxyl group of the aspartate residue is conjugated with -NH-NH-CONH2. (#) The numbers indicate the positions of peptide fragments in the amino acid sequence of CTX1 and CTX3, and the parentheses indicate the aspartate residues in the peptide fragments.