Amylin

Amylin plays a role in glycemic regulation by slowing gastric emptying and promoting satiety, thereby preventing post-prandial spikes in blood glucose levels.

[10] The terminal glycine amino acid that results from this cleavage allows the enzyme peptidylglycine alpha-amidating monooxygenase (PAM) to add an amine group.

[11] Insulin and IAPP are regulated by similar factors since they share a common regulatory promoter motif.

[12] The IAPP promoter is also activated by stimuli which do not affect insulin, such as tumor necrosis factor alpha[13] and fatty acids.

[15] It thus functions as a synergistic partner to insulin, with which it is cosecreted from pancreatic beta cells in response to meals.

The overall effect is to slow the rate of appearance (Ra) of glucose in the blood after eating; this is accomplished via coordinate slowing down gastric emptying, inhibition of digestive secretion [gastric acid, pancreatic enzymes, and bile ejection], and a resulting reduction in food intake.

The human form of IAPP has the amino acid sequence KCNTATCATQRLANFLVHSSNNFGAILSSTNVGSNTY, with a disulfide bridge between cysteine residues 2 and 7.

Within the fibrillization reaction, the early prefibrillar structures are extremely toxic to beta-cell and insuloma cell cultures.

In particular, the impaired processing of proIAPP that occurs at the N-terminal cleavage site is a key factor in the initiation of amyloid.

[10] Thus, the conditions of Type 2 diabetes—high glucose concentrations and increased secretory demand for insulin and IAPP—could lead to the impaired N-terminal processing of proIAPP.

In summary, impaired N-terminal processing of proIAPP is an important factor initiating amyloid formation and β-cell death.

This suggests that repairing proIAPP processing may help to prevent β-cell death, thereby offering hope as a potential therapeutic approach for Type 2 diabetes.

While the association of amylin with the development of type 2 diabetes has been known for some time,[citation needed] its direct role as the cause has been harder to establish.

Some studies suggest that amylin, like the related beta-amyloid (Abeta) associated with Alzheimer's disease, can induce apoptotic cell-death in insulin-producing beta cells, an effect that may be relevant to the development of type 2 diabetes.

The study combined metreleptin, a version of the human hormone leptin, and pramlintide, which is Amylin's diabetes drug Symlin, into a single obesity therapy.

[36][37] Another long- acting analogue of Amylin is Cagrilintide being developed by Novo Nordisk ( now in the Phase 3 trials with the proposed brand name CagriSema co- formulated with Semaglutide as a once weekly subcutaneous injection ) as a measure to treat type II DM and obesity.

Amino acid sequence of amylin with disulfide bridge and cleavage sites of insulin degrading enzyme indicated with arrows
General Scheme for Amyloid Formation