期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1979
卷号：76
期号：6
页码：2960-2963
DOI：10.1073/pnas.76.6.2960
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The existence of a functionally immature fetal albumin has been postulated to explain the reduced ability of newborn plasma to bind bilirubin and various drugs. In support of this, cord and adult albumin, isolated by a simple salting-out technique, were reported to differ in electrophoretic and chromatographic properties and in their resistance to alkali and proteolytic enzymes. However, the interpretation of these findings has since been questioned. To resolve this controversy, we have purified to homogeneity human serum albumins from pooled umbilical cord and adult donor plasma. The two albumins were compared and found to be indistinguishable by polyacrylamide gel electrophoresis with and without sodium dodecyl sulfate, as well as by immunoelectrophoresis and double immunodiffusion using specific antibodies against both albumins. Furthermore, the amino acid compositions, the aminoterminal sequence (Asp-Ala-His-Lys-Ser-Glu-Val-Ala-), the carboxy terminus (Leu), and the peptide fingerprints were identical in the two albumins. No significant differences were found by circular dichroism in the ultraviolet (200-350 nm). Binding studies with bilirubin showed association constants of 3.7 {+/-} 0.7 x 107 M-1 for cord and 2.9 {+/-} 0.3 x 107 M-1 for adult albumin, respectively. The circular dichroic spectra of 1:1 bilirubin{middle dot}albumin complexes showed considerable variation between the batches but were not significantly different. The only difference was found in the fluorescence spectra of the bilirubin{middle dot}albumin complexes, in which complexes with adult albumin showed only 75% of the relative fluorescence exhibited with cord albumin. The combined results nevertheless strongly indicate that fetal and adult albumins are very similar, if not identical.
关键词：neonatal medicine ; bilirubin binding ; immunochemistry ; protein structure ; spectroscopy
