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Biomedical subjects

Y Niitsu

Publications and source records attributed to Y Niitsu.

At least 361 records · Page 20Linked to original sources
PubMed1979

Enzyme immunoassay for human ferritin.

We describe an enzyme immunoassay with use of beta-D-galactosidase for quantitation of ferritin in human serum. The minimum detectable ferritin concentration is 0.25 microgram/L of serum, which is comparable to results obtained by radioimmunoassay. The correlation coefficient between values determined by enzyme immunoassay and radioimmunoassay was 0.95 (n - 1 = 85, p less than 0.001).

Ferritins↗
PubMed1975

Characterization of the different polypeptide components and analysis of subunit assembly in ferritin.

Ferritin was dissociated into subunits by various denaturants and the subunits were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Human, horse, rat, and rabbit ferritins all exhibited characteristic patterns of heterogeneity; components with molecular weights of about 19,000, 11,000, and 8,000 were invariably found in these preparations. This result contradicts earlier reports that ferritin consists of 24 identical subunits. These polypeptides were isolated, purified in the presence of low concentrations of detergent, and characterized. Evidence based on amino acid compositions, NH2-terminal analysis and investigation of detergent-induced breakdown products, indicated that the 19,000 molecular weight component is a composite of the 8,000 and 11,000 molecular weight chains. Circular dichroism studies showed that the 19,000 molecular weight polypeptide retained appreciable amounts of ordered secondary structure whereas the two lower molecular weight peptides were unfolded to a much greater extent. If the 8,000 and 11,000 molecular weight polypeptides were recombined in equimolar amounts and the denaturant was completely removed, a substance with electrophoretic mobility and morphological appearance of native apoferritin was obtained.

Amino Acids↗