Synthesis and Characterization of an A6-A11 Methylene Thioacetal Human Insulin Analogue with Enhanced Stability

Abstract

Insulin has been a life-saving drug for millions of people with diabetes. However, several challenges exist which limit therapeutic benefits and reduce patient convenience. One key challenge is the fibrillation propensity, which necessitates refrigeration for storage. To address this limitation, we chemically synthesized and evaluated a methylene thioacetal human insulin analogue (SCS-Ins). The synthesized SCS-Ins showed enhanced serum stability and aggregation resistance while retaining bioactivity compared with native insulin.

Discovery of Methylene Thioacetal-Incorporated α-RgIA Analogues as Potent and Stable Antagonists of the Human α9α10 Nicotinic Acetylcholine Receptor for the Treatment of Neuropathic Pain

“…In detail, after cleavage of the assembled peptide chain from 2-CTC resin, the Trt protections were removed and the target methylene thioacetal bond was formed by treatment with diiodomethane in the presence of tris(2carboxyethyl)phosphine hydrochloride (TCEP•HCl), potassi-um carbonate, and trimethylamine (Et 3 N). 54,58 This key-step conversion can be conducted in as large as the 300 mg scale in one batch, which enables large preparation of target peptides for further studies. The second disulfide bridge was formed after Acm deprotection by the treatment of excess iodine in 25% aqueous acetic acid (AcOH) to yield fully folded peptides.…”

Cysteine protecting groups: applications in peptide and protein science

“…83 Cys(Mob) has also been incorporated into tripeptide benzyl esters for use as potential DNA intercalators, with the protecting group intact in the final product. 181 Cys(Mob) is also compatible with Fmoc SPPS, as demonstrated in the synthesis of methylene thioacetal human insulin analogue (SCS-Ins), 182 and of LaIT2, a b-KTx 183 peptide that is found in Liocheles australasiae scorpion venom, and displays antimicrobial activity. 184 Cys(Mob) can undergo oxidation to give the corresponding Mob-protected sulfone, Cys(Mob(O)) (Fig.…”

Facile synthesis of insulin fusion derivatives through sortase A ligation

“…Although Ins-SA-Alb is ∼15-fold weaker than native insulin in activating insulin signaling, in STZ-treated diabetic mice, Ins-SA-Alb has a longer half-life than native insulin indicating SrtA ligations are a viable method to produce new insulin fusion derivatives. Notably, because only a couple of mutations are needed in the C-terminal B chain, novel insulin skeletons with therapeutic potentials 32 , 33 can also be modified using this method. We are now applying our method to synthesize other insulin fusion derivatives with therapeutic potentials.…”