生物化学技术

Purification of cytochrome P450 enzymes has played an important role in the development of the field. Although purification of these enzymes is not requisite to many types of investigation, purified enzymes are still required for studies on structure and mechanism. Purified enzymes are ...

Capillary electrophoresis (CE) represents a relatively new separation technology that has gained acceptance in a wide variety of applications. A discussion of the basic theory of CE separations is beyond the scope of this presentation, but is well addressed in a number of recent texts (1–5). In p ...

The determination of epitope specificities of monoclonal antibodies (MAbs) has usually been performed using the competitive solid-phase assay in which the antigen is immobilized, and a radiolabeled antibody and competing unlabeled antibodies are mixed in solution (Fig. 1A) (1,2). A ...

The detection of free radicals is often carried out by electron spin resonance (ESR) techniques. The procedure is specific and very sensitive (provided the radicals have a sufficiently long half-life to be measured). In the case of extremely short-lived free radicals, which are difficult to d ...

Glutamate is an excitatory transmitter released from neurons. It communicates information rapidly by activating receptors in other neurons (1). Physiologic concentrations of glutamate are 1 μM extracellularly and several millimolar intracellularly. Higher extracellu ...

Radical-mediated protein oxidation was first studied at the beginning of the 20th century by Henry Dakin (; reviewed in ref. 2), but it is only recently that the use of the products of these reactions as specific markers of oxidative damage in in vivo situations has been established. Generic markers of p ...

Measurement of O2 consumption, conjugated dienes, and decomposition products of lipid hydroperoxide (LHP) such as malondialdehyde have been extensively used as markers of lipid peroxidation (1). Glutathione (GSH) and glutathione disulfide (GSSG) are biologically important ...

Protein carbonyls are formed by a variety of oxidative mechanisms and are sensitive indices of oxidative injury (1). The conventional assay for protein carbonyls is a colorimetric procedure that measures binding of dinitrophenylhydrazine (DNP) (2,3). Protein-bound DNP can also be me ...

Protein thiol groups are susceptible to oxidation by reactive oxygen species (1). The occurrence of a specific thiol modification named protein S-glutathionation has been proposed to protect proteins from oxidative damage owing to its reversible characteristics (2–4). In additio ...

The comet assay, or alkaline single-cell gel electrophoresis, originated as a simple and sensitive method for detecting DNA strand breaks in cells such as peripheral blood lymphocytes, cultured cells, and disaggregated tissue, e.g., liver (1,2). Cells embedded in a thin layer of agarose on a mic ...

Reactive oxygen species (ROS) such as hydroxyl radicals ~undefinedOH), superoxide anions (O2 −) and hydrogen peroxide (H2O2) have been shown to damage to chromosomal DNA and other cellular components, resulting in DNA degradation, protein denaturation, and lipid peroxidation (1,2). We know a little ...

Oxygen free radicals (OFR) also known as reactive oxygen species (ROS) are formed as a consequence of normal oxidative metabolism. Their generation goes up substantially under chronic inflammatory conditions and ischemia. These free radicals have multifarious effects that inclu ...

Lipid peroxidation (LPO) is a prominent manifestation of free radical (FR) activity in biological systems. The primary target of FR attack on lipids is the 1,4-pentadiene structure of a polyunsaturated fatty acid (PUFA), which are either free or esterified to cholesterol or glycerol. Initi ...

Xanthine oxidoreductase (XO) catalyses the oxidation of hypoxanthine to xanthine and of the latter to uric acid. The enzyme is present in traces in most of human tissues, including plasma, being more abundant in milk, liver, and intestine (1).

Lipid peroxidation is initialed as activated oxygen reacts with the double bonds on the lipid hydrocarbon chains (1). Depending on the type of lipid, type of oxidant, and severity of the oxidation, a variety of lipid-peroxidation products are formed (1). The major proucts of lipid peroxidation a ...

In the retina, as well as in other organs, inflammation-mediated membrane lipid peroxidation is regarded as the major source of unsaturated fatty acid hydroperoxides. It is generally accepted that inflammatory infiltrates, such as polymorphonuclear leukocytes and macropahges, ...

The term eicosanoid is derived from the chemical name for arachidonic acid, eicosatetraenoic acid. The term eicosanoid includes the prostaglandins (PG), thromboxanes, and leukotrienes (1). Multiple biosynthetic pathways exist for eicosanoid formation (2) and specific eicosa ...

The oxidation of lipids can cause the formation of lipid hydroperoxide followed by the degradation of the peroxide. The formed lipid-decomposition products such as aldehydes can easily react with biomolecules such as proteins (1). The aldehyde-derived adduct formation has been exam ...

Uptake of oxidized low-density lipoprotein (LDL) by scavenger receptors allows cholesterol to be accumulated in an unregulated fashion by cells in the artery wall, an event considered pivotal to the formation of atherosclerotic plaques (1). High-density lipoprotein particles (HD ...

Free radicals derived primarily from molecular oxygen are believed to play an important role in a variety of disease processes including atherosclerosis, cancer, and neurodegenerative disorders (1). Much of the evidence for this association, however, is indirect largely because of l ...