The gene GUCA2B at 1p34-p33 codes for the 112 amino acid peptide guanylate cyclase activator 2B. This is split into :
- Guanylate cyclase C-activating peptide 2(GCAP-II)
- 24 amino-acids from 89 – 112.
- Last 16 amino-acids
The GUCA2B gene has several binding sites for the promoter-specific proteins transcription factor AP-1 and transcription factor AP-2, and a cAMP-regulated enhancer element. It is expressed mainly in the small intestine but also in both the atria and ventricles of the heart.