Synthetic peptides insulin

Octreotide -synthetic peptide analogue of somatostatin -abdominal pain, nausea, vomiting, diarrhea -local injection site reactions -cholelithiasis -sweating, flushing -hyperglycemia (many patients will require insulin therapy)... 

Octreotide acetate (Sandostatin) is a synthetic peptide analogue of the hormone somatostatin. Its actions include inhibition of the pituitary secretion of growth hormone and an inhibition of pancreatic islet cell secretion of insulin and glucagon. Unlike somatostatin, which has a plasma half-life of a few minutes, octreotide has a plasma elimination half-Hfe of 1 to 2 hours. Excretion of the drug is primarily renal. 

Synthetic peptides such as oxytocin, vasopressin, ACTH, calcitonin, secretin, somatostatin, cyclosporine, and insulin are already in clinical use. 

Fig. 3. Artificial substrates for the insulin receptor tyrosyl kinase. Shows the Km values exhibited by basal and insulin-stimulated kinase activities together with the insulin-stimulated increase in Vmax for a variety of substrates. These include angiotensin and its modified derivative (VAL-5), also synthetic peptides of Glu Tyr and the so-called sarc -peptide, which bears the sequence around the tyrosyl autophosphorylation site of the sarc protein. Data are also given for a G-protein mixture of Gj/G0. These studies (referred to in the text) all employed soluble, purified insulin receptor preparations. No evidence has yet been presented for tyrosyl phosphorylation of substrates using isolated membrane preparations containing insulin receptors.

A number of synthetic peptides are significant commercial products, ranging from the sweet dipeptide aspartame (L-aspartyl-L-phenylalanine methyl ester) to clinically used hormones such as insulin and oxytocin. L-Aspartyl-L-phenylalanine methyl ester (3 Scheme 2) is the methyl ester of the C-terminal dipeptide of gastrin. It was found accidently during the synthesis of gastrin that this synthetic sweetener is about 200 times as sweet as sucrose.f This pleasant sweetness without a bitter aftertaste was the reason that L-aspartyl-L-phenylalanine methyl ester was approved in many countries as a food additive, receiving much attention as a low-calorie sweetener. L-Aspartyl-L-phenylalanine methyl ester can be prepared by various chemical routes and the first enzymatic procedure of commercial interest was described by Isowa et al.h l In the industrial process,L-Asp and DL-Phe were chosen as inexpensive raw materials. L-Asp is available very inexpensively, whereas L-Phe is more expensive than DL-Phe. Z-D-Asp acts as a competitive inhibitor, while D-Phe-OMe... 

Table 5 verifies the low permeability of the monolayer to a number of proteins ranging in molecular weight from a 5000 kDa random synthetic peptide with primarily hydrophilic amino acids to a 600,000 kDa conjugate of albumin and superoxide dismutase with an average molar ratio of approximately 10 1. The movement of these molecules across the monolayer over a 4-hour period is extremely slow and only slightly above background. Insulin and LDL cross the monolayer quite effectively and in a concentration-dependent manner. These experiments verify earlier work from King s laboratory [2,8]. Furthermore, when... 

In a study of the action of proteolytic enzymes on an oxidation product (fraction B, p. 54) of insulin, Sanger and Tuppy (1951b) found that other bonds besides those adjacent to aromatic residues were split by pepsin, including those of Leu-Val, Ala-Leu, and Glu(—NH2)-His. It thus seems that in the case of pepsin at least there is much to be learnt about its specificity when proteins act as substrate. Trypsin and chymotrypsin were found to split oxidized insulin with the same specificity as was found for synthetic peptides, and it seems probable that this specificity may be shown in their action on other proteins. Clearly a knowledge of the exact mode of action of these enzymes would greatly help in the elucidation of protein structure just as advances in our knowledge of protein structure must throw light on the behavior of the endopeptidases. 

Galparan, GWTLNSAGYL10lGPINLKALA ALAKKILa, a chimeric 27-peptide consisting of the N-terminal sequence 1-13 of galanin linked to mastoparan via a peptide bond. This synthetic peptide powerfully stimulates insulin secretion... 

Lin PY, Hung SH, Yang YC, Liao LC, Hsieh YC, Yen HJ, et al. A synthetic peptide-acrylate surface for production of insulin-producing cells from human embryonic stem cells. Stem Cells Dev 2014 23 372-9. 

Numerous methods have been developed for the formation of disulfide bonds in recombinant DNA-derived and chemically synthesized peptides and proteins, but only a few have foimd widespread acceptance. The choice of method(s) for formation of disulfide in synthetic peptides and proteins needs to be tailored for each individual polypeptide in such a way so that the reaction conditions are selective, efficient, and safe and give the maximum yield. Here we describe the sequential formation of three disulfide bonds regioselectively which has been optimized for the synthesis of two-chained, heterodimeric polypeptide members of the insulin-relaxin superfamily. 

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