Table 3.
Masses of methyl esterified forms of putative peptides produced from (Hoa)-prepro-orcokinin and exact mass measurements for those peptides detected in methyl esterified tissue extracts from a single SG or paired CoGs from Homarus americanus using MALDI-FTMS.
| Sinus gland (SG)a |
Commissural ganglia (COG)a |
|||
|---|---|---|---|---|
| Sequence, Peptide | Ion Identity | Calculated m/z |
Measured m/zb |
Measured m/zb |
| NFDEIDRSGFGFH [His13]-orcokinin | [M+H]+ | 1596.7441 | 1596.7437 (−0.2) |
1596.7388 (−3.4) |
| NFDEIDRSGFGFN [Asn13]-orcokinin | [M+H]+ | 1573.7282 | 1573.7339 (3.6) |
1573.7221 (−3.8) |
| NFDEIDRSGFGFV [Val13]-orcokinin | [M+H]+ | 1558.7536 | 1558.7514 (−1.4) |
1558.7446 (−5.8) |
| SSEDMDRLGFGFN Hom-orcokinin | [M+H]+ | 1530.6893 | 1530.6901 (0.5) |
1530.6844 (−3.2) |
| FDAFTTGFGHN OMT | [M+H]+ | 1241.5586 | 1241.5622 (2.9) |
1241.5619 (2.7) |
| VYGPRDIANLY (Hoa-OPRP III) | [M+H]+ | 1308.6947 | 1308.6946 (−0.1) |
1308.6884 (−4.8) |
| GDYDVYPE (Hoa-OPRP II) | [M+H]+ | 1093.4030 | ND | ND |
| [M+Na]+ | 1115.3850 | ND | ND | |
| GDY(SO3)DVYPE (Hoa-OPRP II) | [M+H]+ | 1013.4462 | ND | ND |
| [M+Na]+ | 1035.4282 | ND | ND | |
| APARSSPQQDAAA GYTDGAPV (Hoa-OPRP I) | [M+H]+ | 3781.0436 | ND | ND |
| GPIKVRFLSAIFIPI AAPARSSPQQDAA AGYTDGAPV (Hoa-OPRP Ia) | [M+H]+ | 2072.0043 | ND | ND |
| SAE (Hoa-OPRP IV) | [M+H]+ | 334.16088 | ND | ND |
| Truncated Orcokinins | ||||
| NFDEIDRSGFGF Orc [1-12] | [M+H]+ | 1459.6852 | 1459.6867 (1.0) |
1459.6823 (−2.0) |
| NFDEIDRSGFG Orc [1-11] | [M+H]+ | 1312.6168 | 1312.6193 (1.9) |
1312.6151 (−1.3) |
| NFDEIDRSGF Orc [1-10] | [M+H]+ | 1255.5953 | 1255.5996 (3.4) |
ND |
a
Single sinus glands or paired commissural ganglia tissues were subjected to solvent extraction followed by methyl esterification. The methyl esterified extracts were analyzed using DHB as the matrix.
b
Exact mass measurements using poly(propylene glycol) 725 and 2000 as calibrants, number in parentheses is the mass measurement error in ppm, ND= not detected.