Biomedical subjects

M K Cha

Publications and source records attributed to M K Cha.

21 records · Page 2Linked to original sources

PubMed1994

The thiol-specific antioxidant protein from human brain: gene cloning and analysis of conserved cysteine regions.

The complete cDNA encoding human thiol-specific antioxidant protein (PRP) was isolated from a human brain cDNA library in the lambda Zap expression vector. An open reading frame (ORF) was identified and found to encode a polypeptide of 197 aa with a M(r) of 21,729. The cDNA contained 98 bp of 5'-untranslated sequence (UTR) and 259 bp of 3'-UTR containing a poly(A) signal, AATAAA. Expression of the human PRP cDNA in Escherichia coli yielded a functionally active protein. The observed local sequence homologies between human PRP and other homologous proteins whose functions have not yet been defined give important insight into elucidating the biochemical function of a new protein family which has highly conserved regions containing cysteine.

Amino Acid Sequence↗

PubMed1994

Purification and characterization of thiol-specific antioxidant protein from human red blood cell: a new type of antioxidant protein.

A thiol-specific antioxidant protein (Protector Protein, PRP) was purified from human red blood cells (RBC). The PRP exists as a predominant protein in human RBC, which showed distinct thiol-specific antioxidant activities in the presence of dithiothreitol (DTT) as a reducing equivalent. The human RBC PRP (HRPRP) completely inhibited visible absorption spectral changes of oxyhemoglobin, DNA cleavage, and the peroxidation of RBC membrane by a nonenzymatic Fe3+/O2/thiol mixed-function oxidation system capable of generating hydroxyl radical. These observations suggest that HRPRP could act as a new type of antioxidant protein to maintain the RBC integrity by scavenging reactive oxygen species.

Antioxidants↗

PubMed1993

Removals of hydrogen peroxide and hydroxyl radical by thiol-specific antioxidant protein as a possible role in vivo.

Thiol-specific antioxidant protein (Protector Protein; PRP) from Saccharomyces cerevisiae was found to remove hydrogen peroxide and hydroxyl radical in the presence of dithiothreitol (DTT). Without DTT as a reducing equivalent, the antioxidant protein did not show the activities for destroying hydrogen peroxide and hydroxyl radical. N-ethylmaleimide (NEM) was observed to prevent the PRP from both removing hydrogen peroxide and protecting the cleavage of DNA. These observations suggest that the sulfhydryl of cysteine in PRP could function as a strong nucleophile to attack and destroy H2O2 and .OH.

Antioxidants↗