Human preproinsulin: translation, MW and pI (insulin@1)

Worked example

• Human insulin coding sequence (NM_000207.3, bases 60 to 392): translated in frame 1 it gives the 110-residue preproinsulin, UniProt P01308.
• Translated in frame 1 with the standard code: 110 residues, 11980.91 Da, pI 5.22, ε280 17,335 M⁻¹cm⁻¹ with the six cysteines paired (ProtParam's residue masses and pK set, Pace et al. 1995 coefficients).
• Source: RefSeq NM_000207.3 (NCBI, public domain); UniProtKB P01308, The UniProt Consortium (CC BY 4.0).

This page is the example insulin@1: its method versions are pinned, so it gives the same numbers next year. seq 1.1.0, 2026-10-06.

Method

Codons read from the frame's first complete codon; the table's amino acid, * for a stop, X when an ambiguity code leaves the amino acid open

• Translation with NCBI's genetic code tables. NCBI. The Genetic Codes, gc.prt version 4.6 (last modified 10 June 2020), fetched 2026-10-06. Public domain.Checked against Biopython 1.88 exactly on 108 frame translations of three sequences in genetic codes 1, 2 and 11, full length and to the first stop, and on 5 annotated coding sequences (6 October 2026).
• Average molecular weight from the sequence. ExPASy ProtParam (Gasteiger et al. 2005); the fixtures are ProtParam's printed weights, retrieved 5 October 2026.Checked against Expasy ProtParam within 0.01 Da on 22 sequences with ProtParam's residue masses (6 October 2026). ProtParam is a tool of the SIB Swiss Institute of Bioinformatics; not affiliated.
• Theoretical isoelectric point. Bjellqvist B et al. Electrophoresis 1993;14:1023-1031; 1994;15:529-539; as ExPASy ProtParam applies them.Checked against Expasy ProtParam within 0.01 on 22 sequences, never a bound of the pH 0 to 14 search (6 October 2026). ProtParam is a tool of the SIB Swiss Institute of Bioinformatics; not affiliated.
• Molar extinction coefficient at 280 nm. Pace CN, Vajdos F, Fee L, Grimsley G, Gray T. How to measure and predict the molar absorption coefficient of a protein. Protein Sci 1995;4:2411-2423 (read 5 October 2026).Checked against Expasy ProtParam exactly on 22 sequences in both cysteine conventions (6 October 2026). ProtParam is a tool of the SIB Swiss Institute of Bioinformatics; not affiliated.