The number of total disulfide bonds in rabbit and sheep 7S gamma globulin, before and after treatment with 2-mercaptoethanol, has been measured by amperometric titration. Mercaptan reduction could diminish the complement-fixing efficiency of 7S rabbit gamma globulin by no more than 90 per cent without any significant decrease in maximal complement-fixing ability. This was associated with the re...

Native disulfide bond formation is essential for the folding of many proteins. The enzyme protein disulfide isomerase (POI) catalyzes native disulfide bond formation using a Cys-Gly-HisCys active site. The active-site properties of POI (thiol pK. = 6.7 and disulfide E;O' = -180 mY) are critical for efficient catalysis. This Dissertation describes the design, synthesis, and characterization of s...

The ER (endoplasmic reticulum) has long been considered the plant cell compartment within which protein disulfide bond formation occurs. Members of the ER-located PDI (protein disulfide isomerase) family are responsible for oxidizing, reducing and isomerizing disulfide bonds, as well as functioning as chaperones to newly synthesized proteins. In the present study we demonstrate that an abundant...

Irradiation of proteins with intense X-ray radiation produced by third-generation synchrotron sources generates specific structural and chemical alterations, including breakage of disulfide bonds and decarboxylation. In this paper, disulfide bond lengths in irradiated crystals of the enzyme Torpedo californica acetylcholinesterase are examined based on quantum simulations and on experimental da...

Insulin-like growth factor I (IGF-I or somatomedin C) is a serum polypeptide with three intramolecular disulfide bonds. In the course of synthesis by the recombinant DNA method, three disulfide bond isomers, all of which have Cys18-Cys61 with three combinations of two disulfide bonds formed by Cys6, Cys47, Cys48 and Cys52, were identified. Natural type, isomer II, was proved to have a Cys6-Cys4...

In order to characterize possible disulfide-linked interactions between lens fiber cell membranes and crystallins, two-dimensional diagonal electrophoresis has been used in combination with Western blot analysis. When these blots were probed with monospecific antisera against alpha, beta and gamma crystallins, membrane from five individual normal lenses showed no disulfide-bonded components. Me...

Disulfide bonds are widespread in peptides and proteins where they strengthen conformation and lead to increased rigidity and proteolytic stability. The number of disulfide-rich therapeutics currently available is increasing, such as the FDA-approved peptide drugs Prialt (ziconotide) and Linzess (linaclotide), both of which contain 3 disulfide bonds. In order to prepare disulfide-rich peptides,...

Disulfide bonds are ubiquitous in proteins. According to a recent survey, there are 97 741 disulfide bonds in 121 779 protein structures available in the Protein Data Bank (PDB).1 Native2,3 as well as engineered4-6 disulfide bonds have been shown to control the stability and function of proteins. The redox state of protein disulfide bonds in vivo, governing protein stability and function, depen...