Abstract
The qualitative and quantitative characterization of amniotic fluid proteins is important for an assessment of fetal developmen and for potential prenatal diagnosis. Low molecular weight proteins (molecular weight ≤ 12,000 daltons) in human amniotic fluid have not been investigated extensively. Fractionation of third trimester human amniotic fluid by Biogel P10 chromatography yielded at least 6 polypeptides ≥ 2000 ≤ 13,000 daltons. The predominant peak, with a molecular weight range of 4 to 6,000 daltons, was separated by DEAE chromatography on a linear NaCl gradient, which yielded two peptide species at 0.55M NaCl and 0.87 NaCl. The 0.55M NaCl peptide (AFP3-4A) proved to be homogeneous by paper chromatography and Biogel P6 column chromatography. The molecular weight was found to be approximately 4200 daltons. The amino acid composition was determined by Durrum high pressure chromatography following acid hydrolysis. 37 amino acid residues were found including trace ornithine concentration and absence of cysteine and methionine. The most abundant amino acids were glycine, glutamic, aspartic acids, alanine and serine. The presence of hexosamine, elution time indistinguishable from glucosamine, was also found. One mole of putrescine was covalently bound per mole peptide. This unusual polypeptide has similar structural characteristics to the plasma putrescine-conjugated polypeptide, putrescinin recently described by us.
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Chan, WY., Seale, T., Shukla, J. et al. 174 CHARACTERIZATION OF A POLYAMINE-CONJUGATED, LOW MOLECULAR WEIGHT POLYPEPTIDE IN HUMAN THIRD TRIMESTER AMNIOTIC FLUID. Pediatr Res 12 (Suppl 4), 392 (1978). https://doi.org/10.1203/00006450-197804001-00179
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DOI: https://doi.org/10.1203/00006450-197804001-00179