Why the first recombinant product had 192 residues and the current one has 191

Published 24 October 2026 · REVIVE LAB UAE Research Desk · 5 min read
Expression inside E. coli starts every protein with methionine, and the bacterial enzyme that removes it does not act efficiently when the next residue is phenylalanine, as in growth hormone. The first recombinant product therefore carried an extra amino-terminal methionine and was named somatrem. Later processes directed the protein to the periplasm with a signal peptide whose cleavage leaves the natural sequence; that product is somatropin, the international nonproprietary name for the 191-residue protein.

Where the methionine comes from

Translation initiates at a methionine codon. Methionine aminopeptidase removes it when the second residue is small; phenylalanine is large, so the methionine stays. Somatrem is otherwise identical to the natural hormone.

Antibodies against the methionyl form were reported more often than against the natural sequence, one reason the industry moved on.

How it was removed

Fusing a bacterial signal sequence to the hormone sends it across the inner membrane, where signal peptidase cleaves precisely at the junction and releases the mature 191-residue chain into the periplasm. Alternative routes used cleavable fusion partners or mammalian cells, which process the native signal peptide themselves.

Each route gives the same final sequence, which is what the name somatropin denotes.

The catalogue product

The product page states somatropin, 191 amino acids. The batch documentation confirms the intact mass, which distinguishes 191 from 192 residues by the mass of one methionine.

Somatropin is supplied by REVIVE LAB UAE for laboratory research use only, with identity and purity documented for the batch. It is not for human or veterinary use, and no dosing, administration or protocol guidance is provided.

What it costs

FormatStrengthPriceAvailability
HGH Somatropin Pack24 mg (72 IU)AED 850In stock

Delivery is AED 40 flat and free on orders over AED 700. Payment is cash on delivery anywhere in the UAE, or USDT (TRC20) in advance, which takes 5% off the order total.

Frequently asked

Where the methionine comes from?

Translation initiates at a methionine codon. Methionine aminopeptidase removes it when the second residue is small; phenylalanine is large, so the methionine stays. Somatrem is otherwise identical to the natural hormone.

Does REVIVE LAB UAE provide dosing guidance?

No. REVIVE LAB UAE supplies research materials and provides no dosing, administration or protocol guidance of any kind. Every product is sold for laboratory research use only and is not for human or veterinary consumption.

How fast is delivery in the UAE?

Stock is held in Dubai. An order confirmed before 4 PM Dubai time is dispatched the same working day, reaching Dubai and Abu Dhabi the same day and the remaining emirates within 24 hours. Delivery is AED 40 flat and free over AED 700.

HGH Somatropin Pack — in stock, dispatched from Dubai
HPLC-verified, lot certificate on every carton, 24-hour delivery nationwide. Browse the catalogue → All peptides UAE

Related reading

Supplied for laboratory research use only. Not for human or veterinary consumption. REVIVE LAB UAE provides no dosing, administration or protocol guidance.