This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
All are TRUE about Gastrin, EXCEPT: 
Select and explain. 
A. Precursor is preprogastrin, B. It has two major form G 34 and G 17, C. Common feature of all gastrin is an amidated tetrapeptide, D. Glycine extended gastrin is produced by gastric mucosal cells
D: Glycine extended gastrin is produced by gastric mucosal cells
Answer: D: Glycine extended gastrin is produced by gastric mucosal cells 
Explanation: Gastrin is produced from the endocrine cells of the gastric antrum. GASTRIN FUNCTION 1. Stimilate gastric acid secretion 2. Growth promotion of gastric mucosa and some cancers Precursor is: Preprogastrin - It has a 101 aminoacid structure. Gastrin has two major forms: G 34 and G 17. Common feature of all Gastrins: Amidated tetrapeptide (Try- Met-Asp-Phe-NH2) Glycine extended gastrin is the non amidated form of Gastrin. It is produced by colonic mucosa. It stimulates proliferation of normal colonic mucosa. In animals it stimulate the development of colorectal cancer. Ref: Sleisenger and Fordtrans, Edition-9, Page-6.