To introduce a free sulfhydryl into Pseudomonas aeruginosa exotoxin A (ETA), methionine 161 in domain I of the toxin was changed to cysteine by site-directed mutagenesis. The free sulfhydryl provides a convenient site for covalent attachment of ETA to other proteins in the production of chimeric toxins. The mutation was then introduced into a variant of ETA that is impaired in receptor binding,...

A procedure is described for the purification of cyclic adenosine 3’,5’-monophosphate receptor protein (CRP) from Escherichia coli involving chromatography on DEAE-cellulose and phosphocellulose, (NH4)&04 precipitation, and filtration on Sephadex G-100. The preparation appears to be homogeneous as determined by sedimentation equilibrium studies, isoelectric focusing, and amino-terminal amino ac...

The poorly known mechanism of inhibition of cholinesterases by inorganic mercury (HgCl2) has been studied with a view to using these enzymes as biomarkers or as biological components of biosensors to survey polluted areas. The inhibition of a variety of cholinesterases by HgCl2 was investigated by kinetic studies, X-ray crystallography, and dynamic light scattering. Our results show that when a...

Ovalbumin-derived peptides IFYCPIAIM, NIFYCPIAIM and YCPIAIMSA, containing a common region YCPIAIM, were previously identified as aggregation-prone with variable fibril formation. In this study, we elucidated self-assembly mechanisms of the peptides, by determining influence on sulfhydryl group accessibility. The free content antioxidant capacity results demonstrate that assemble into β-sheets,...

Organomercurial diuretics stimulate renin secretion although the underlying cellular mechanisms remain undefined. Since organomercurials are also known to react with sulfhydryl groups, the present studies determined the effects of sulfhydryl reagents on renin secretion. The effects of the non-diuretic mercurial agent, parachloromercuriphenyl-sulfonate (PCMPS), as well as that of other sulfhydry...

Background and objectives Wheat gluten (WG) often co-exists with egg white (EW) whey proteins in foods. This study investigated the impact of WG on denaturation hen (S-)ovalbumin [(S-)OVA], lysozyme (LYS), bovine serum albumin (BSA). Findings caused peak temperature LYS BSA to increase that (S-)OVA decrease. It accelerated decelerated OVA, respectively, their lowered activation energy. In contr...

BACKGROUND The hepatitis B virus is a significant pathogen that causes cirrhosis, and hepatocellular cancer as a result of the damage it causes to liver cells. Its infection affects more than 400 million people globally. Although there is an effective vaccine and treatment methods, almost 1, 000, 000 people die every year. OBJECTIVE To investigate paraoxonase and arylesterase activities along...

Greenstein and Edsall (1) in early observations on the quantitative estimation of sulfhydryl groups in the muscle protein myosin classified the SH groups of the native protein into “free” and unavailable groups on the basis of porphyrindine titration with nitroprusside as an external indicator. In subsequent experiments, Singer and Barron (2) observed that combination of the “free” groups of my...