Microfilaments undergo an ATP-dependent disruption into shortened bundles following cellular exposure to oxidants. This phenomenon does not require a net change in the amount of polymerized actin. However, increased amounts of polymerized actin have been detected in oxidant-injured cells and it was the purpose of this study to determine the conditions under which the actin polymerization may oc...

Studies of isolated intact spinach (Spinacia oleracea L.) chloroplasts reveal that most of the available sulfhydryl groups are associated with stromal protein as opposed to a thylakoid membrane fraction under non-denaturing conditions. Increases in sulfhydryl content of approximately 50% occurred with illumination and could be correlated kinetically with a reductive activation of fructose-1,6-b...

A method is described for purification of sulfhydryl oxidase from bovine milk which consistently yields preparations with greater than 3000-fold purification over skim milk. A concentration-dependent association-dissociation of the enzyme was adapted to the development of an isolation procedure. Purified preparations exhibited two zones, both of which displayed activity, upon polyacrylamide dis...

The metal cation requirements of pyruvate, phosphate dikinase from Bacteroides symbiosus have been examined with respect to both the overall reaction and the three partial reactions. The overall reaction and all three partial reactions require a divalent cation (M$‘, Mn’+, or Co’+). Although Mn2+ and Co’+ are very effective activators at low concentrations in two of the three partial reactions,...

The sensitivity of growing bacterial cells to destructive agents or influences is many times that of bacterial spores (Curran, 1952). Some of these agents act on sulfhydryl groups of proteins; on the other hand, sulfhydryl groups belong to the most sensitive groups in proteins and are vital for the function of many enzymes (Barron, 1951). The question may be raised whether the degree of resista...

The effect of N-ethylmaleimide (NEM), an irreversible sulfhydryl modifying reagent, on the transport of organic cations in the renal basolateral membrane was examined. The studies were conducted examining the exchange of [3H]tetraethylammonium (TEA) for unlabeled TEA in basolateral membrane vesicles isolated from the outer cortex of rabbit kidneys. NEM inactivated TEA transport in a dose-depend...

Tyrosine hydroxylase (TH) is the initial and rate-limiting enzyme in the biosynthesis of dopamine (DA). TH activity is significantly diminished in Parkinson's disease (PD) and by the neurotoxic amphetamines, thereby accentuating the reductions in DA associated with these conditions. Reactive oxygen and nitrogen species have been implicated in the damage to DA neurons seen in PD and in reaction ...

In cells, the ratio/equilibrium between oxidized and reduced forms of glutathione and between cysteine and cystine (main cells antioxidants) affect thiol balance and redox status of cells and proteins (4). In general, spectroscopic and chromatographic methods are used for quantitative determination of low-molecular thiols and sulfhydryl groups in proteins. Optical methods are employed to detect...

4-Hydroxy-2-nonenal (HNE) is an aldehyde by-product of lipid peroxidation that is presumed to play a primary role in certain neuropathogenic states (e.g., Alzheimer disease, spinal cord trauma). Although the molecular mechanism of neurotoxicity is unknown, proteomic analyses (e.g., tandem mass spectrometry) have demonstrated that this soft electrophile preferentially forms Michael-type adducts ...