Latent TGF beta 1  cDNA encodes a 390 amino acid precursor that contains a 29 aa signal peptide and a 361 aa proprotein. A furin‑like convertase processes the proprotein to generate an N‑terminal 249 aa latency‑associated peptide (LAP) and a C‑terminal 112 aa mature TGF‑ beta 1. Disulfide‑linked homodimers of LAP and TGF‑ beta 1 remain non‑covalently associated after secretion, forming the small latent TGF‑ beta 1 complex.

> 95% as determined by Tris-Bis PAGE