Fragrant unsaturated aldehydes elicit activation of the Keap1/Nrf2 system leading to the upregulation of thioredoxin expression and protection against oxidative stress.

Thioredoxin, a key molecule in redox regulation, and many redox enzymes are regulated through the antioxidant responsive element (ARE). To search for antioxidative constituents, we screened extracts from vegetables and found that the extracts of Perilla frutescens and Artemisia princeps have potent thioredoxin-inducing activities. By activity-guided purification of Perilla frutescens extracts, we identified perillaldehyde as a novel thioredoxin inducer.

Carbohydrate analysis of porcine thyroglobulin isoforms with different iodine contents.

To further validate the relationship between thyroid hormone formation and the carbohydrate structure of thyroglobulin (Tg), we reinvestigated the relationship between the iodine content and the asparagine-linked oligosaccharide structures of porcine Tg. Purified porcine Tg was further separated into isoforms (Tg-F1, -F2 and -F3) with a DEAE-cellulose ion-exchange chromatography column. The iodine residues, neutral sugar and sialic acid were analyzed for the separated Tg isoforms and their asparagine-linked oligosaccharide structures were analyzed.

Determination of sulfhydryl groups in ovalbumin by high-performance liquid chromatography with inductively coupled plasma mass spectrometric detection.

High-performance liquid chromatography (HPLC) interface to inductively coupled plasma mass spectrometry (ICPMS) has been applied for the first time to determine the sulfhydryl groups (SHs) in chicken ovalbumin (OVA) after their conversion into mercaptides with organic mercury compounds. The procedure is based on the HPLC separation of mercury mercaptide OVA followed by ICPMS detection of mercury. The rates of reaction of five mercaptide-forming reagents with SHs in OVA were in the order ethylmercuric chloride > mersalyl acid > p-chloromercuribenzoate > p-(chloromercuri)benzenesulfonic acid > fluorescein mercuric acetate.

Formation of porphyrin pi-cation radical in myoglobin. A study on one electron oxidation products of nickel (II)-substituted hemoproteins.

Nickel (II)-substituted myoglobin (Mb), hemoglobin (Hb) and horseradish peroxidase (HRP) were oxidized with iridate to examine whether porphyrin pi-cation radical is formed or not in these hemoproteins. It was found that Ni (II)-porphyrin pi-cation radical is formed in all of these hemoproteins as confirmed by UV-visible and ESR spectra, although the porphyrin pi-cation radical in Mb and Hb was less stable than in HRP. These results are discussed in relation to the different features of higher oxidation states of native Mb and HRP.