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...

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...

The lubrication phenomenon is used to reduce friction and wear between two rubbed surfaces, such as in engine cutting processes. Different oils mineral oil synthetic lubricant are being for this purpose. With the passage of time, demand energy will get higher natural resources lubricants be diminished. Furthermore, biodegradation too slow, it remains on surface earth a long period creating atmo...

The ionizing radiation sensitivity of ricin, a disulfide-linked heterodimeric protein, was studied as a model to determine the ability of disulfide bonds to transmit destructive energy. The radiation-dependent loss of A chain enzymatic activity after irradiation of either intact ricin or ricin in which the interchain disulfide bond was disrupted gave target sizes corresponding to the molecular ...

Radical induced disulfide bond cleavage in peptides was demonstrated by ultraviolet (UV) radiation of the electrospray ionization (ESI) plume using a low pressure mercury (LP-Hg) lamp. Tandem mass spectrometry and accurate mass measurements confirmed that the primary reaction products were due to disulfide bond cleavage to form thiol (-SH) and sulfinyl radical (-SO˙). Mechanistic studies showed...

The thiol-disulfide oxidoreductase ERp57 is a soluble protein of the endoplasmic reticulum and the closest known homologue of protein disulfide isomerase. The protein interacts with the two lectin chaperones calnexin and calreticulin and thereby promotes the oxidative folding of newly synthesized glycoproteins. Here we have characterized several fundamental structural and functional properties ...