Table 1.
VGF assay characterization.
| Antisera | Peptide | IC50 pmol/ml | CV1 % | CV2 % | Cross-reactivity % |
|---|---|---|---|---|---|
| rVGF C-term. | rVGF609–617 (IEHVLLHRP)1 | 0.02 | 2–3 | 8–10 | 100 |
| hVGF607–615 | <0.01 | ||||
| hVGF603–612 | <0.01 | ||||
| TLQP | rVGF556–564 (TLQPPASSR)2 | 1.1 | 3–5 | 10–13 | 100 |
| rVGF555–564 R-TLQPPASSR* | 3.5 | ||||
| rVGF556–566 (TLQP-11) | 122 | ||||
| rVGF556–576 (TLQP-21) | 183 | ||||
| rVGF N-term. | rVGF24–31 (APPGRSDVYP) 3 | 10 | 3–7 | 9–12 | 100 |
| hVGF23–30 | <0.001 | ||||
| mVGF24–31 | <0.001 | ||||
| NERP-4 | rVGF489–497 (NAPPEPVPP) 4 | 6 | 5 | 6–9 | 100 |
| rVGF489–507 | 95 | ||||
| rVGF488–496 | <0.001 | ||||
| NERP-3 | rVGF197–206 (LESPGPERVW) 5 | 10 | 8 | 5–8 | 100 |
| rVGF197–207 | <0.001 | ||||
| hVGF177–206 | 90 | ||||
| hVGF199–206 | 98 | ||||
| GGGE | rVGF375–382 (GGGEDEVG) 6 | 0.6 | 3 | 8–10 | 100 |
| hVGF373–380 | <0.001 | ||||
| rVGF375–420 | 150 |
IC50: concentration of peptide producing 50% inhibition of the maximum signal; CV1 and CV2: intra- and inter-assay variation, respectively; h: human; r: rat. 1–6“reference” peptides, used for immunization, plate coating, and as measurement standards, respectively. *Arg-extended: an Arginine residue was added at the peptide N-terminus, to mimic its extended sequence within the VGF precursor. The cross-reactivity of each peptide was expressed compared to the “reference” peptide used in the assay, hence a >100% reactivity is indicated for peptides with higher reactivity (e.g., TLQP-21).