Semax mass & m/z.

Molecular formula C37H51N9O10S · Signaling & Neuroactive. Mass and m/z below are computed from the verified molecular formula; the isoelectric point is computed only where the sequence permits.

Compound page →Open dataset →Sequence calculator →

Molecular mass

Computed from the verified molecular formula.
Average molecular weight	813.93 g/mol
Monoisotopic mass	813.3480 Da

Cross-check: matches the verified record (monoisotopic 813.348 Da, average 813.93 g/mol). Average mass varies ~0.01–0.1 Da between atomic-weight tables.

ESI-MS m/z (positive mode)

Predicted protonated ion series [M+nH]ⁿ⁺, m/z = (M + n·1.007276) / n.
Charge state	m/z (monoisotopic)	m/z (average)
[M+1H]1+	814.3552	814.94
[M+2H]2+	407.6813	407.97
[M+3H]3+	272.1233	272.32
[M+4H]4+	204.3443	204.49

Isoelectric point (pI)

5.36

Method: Henderson–Hasselbalch net-charge bisection. pKa set: EMBOSS. Assumptions: Linear peptide, free N- and C-termini, standard 20 L-amino acids, no post-translational modifications. Published pKa sets differ, so treat pI as method-dependent (±~0.3).

Method & provenance

Mass: element arithmetic over the verified molecular formula. Monoisotopic uses most-abundant-isotope masses (CODATA/AME); average uses IUPAC 2021 standard atomic weights.
ESI-MS m/z: positive-mode protonated ions [M+nH]ⁿ⁺, m/z = (M + n·1.007276) / n, from the computed monoisotopic (and average) mass.
pI: computed only for linear, unmodified peptides of the standard 20 L-amino acids with free termini; otherwise flagged. Values are analytical/characterization data only — no efficacy, dosing, or human-use meaning.

Related resources

More signaling & neuroactive analytics

Analytical reference