TCI America Chlorogenic Acid Hydrate C0181

Chlorogenic Acid Hydrate / 3-(3,4-Dihydroxycinnamoyl)quinic Acid
In this section, proteases are categorized into three modes of actions: (1) serine protease; (2) cysteine protease; (3) metalloprotease.1)
Serine proteases are inhibited by AEBSF, benzamidine, etc.2) Cysteine proteases are inhibited by compounds which react with SH groups such as 2-iodoacetamide or 2-iodoacetic acid.3) Metalloproteases are inhibited by chelating agents, EDTA or 1,10-phenanthroline.4)
In the course of protein extraction, proteolysis is considered to be a major problem because it leads to decreasing yields. Addition of protease inhibitors helps to avoid the proteolysis and improves recovery of the desired protein.5) In the experiment of immunoprecipitation, protease inhibitors are also used to avoid decomposition of antigens or antibodies by proteolytic impurities.6) Protease inhibitors which are frequently used in biochemical research are illustrated in this section.
Thiol protease inhibitors, 2-iodoacetamide and 2-iodoacetic acid, cannot be used in protein extraction, because they form covalent bonds to the SH group of the proteins. In protein research, they are used as an alkylation reagent to derivatize the proteins which are extracted from an electrophoresis gel for mass spectrometric analysis.7)

Chlorogenic Acid Hydrate / 3-(3,4-Dihydroxycinnamoyl)quinic Acid
Living organisms acquire energy by bringing oxygen into their bodies. However, they can also be damaged by oxidative stress. Hence they maintain complex chemical systems of multiple types of antioxidants, which are chemical substances that protect biological materials against the effects of this stress. Human beings utilize antioxidants in a daily life as food additives to avoid their deterioration. Antioxidants in pharmacology are studied, particularly as treatments of stroke and nerve atrophy diseases. Antioxidants are also widely used as ingredients of functional foods. However, some clinical trials suggested that getting antioxidants during athletic exercise might be harmful. Functioning of the antioxidants remains to be investigated.
• Functions of Antioxidants
(1) Scavenging of active oxygen species and radicals
Scavenging of hydrogen peroxide (H2O2), free radicals such as the hydroxyl radical (•OH), the superoxide anion (O2^?), and the radicals they produce with biological molecules.
(2) Metal inactivation
Chelating metals to inactivate a metal such as iron which promotes oxidation
(3) Oxidase inhibition
(4) Protection of disulfide bond
Inhibition of the oxidative cleavage of disulfide bonds in the proteins.
• Classification of Antioxidants
Antioxidants are classified according to their solubility.
(1) Water-soluble antioxidants
Ascorbic acid (Vitamin C), Glutathione, Lipoic acid.
Typical properties: (a) Neutralization of reactive oxygen species, (b) Inhibition of the cleaving reaction of disulfide bonds.
(2) Fat-soluble antioxidants
α-Tocopherol (Vitamin E), gallates, resveratrol, polyphenols (e.g. ubiquinone, or coenzyme Q10), polyene compounds (e.g. β-Carotene).
Typical properties: Antioxidation of lipids through radical scavenging activity
• Storage Precautions
Solid antioxidants can be stored in a cool and dry place, unless otherwise specified. After opening, they should be stored under inert gases such as nitrogen or argon to prevent their oxidation. Since oily antioxidants can deteriorate faster than solids, they should be stored under an inert gas in a refrigerator. Refrigerated antioxidants should be warmed in a desiccator at room temperature under ambient atmosphere just before use without opening the cap. This operation can avoid moisture uptake of the reagents.