Proteins from the organic matrix of core-top and fossil planktonic foraminifera

Journal Article · Wed Aug 01 04:00:00 EDT 1990 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(90)90052-M· OSTI ID:5982203

Robbins, L L ^[1]; Brew, K ^[2]

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1. Univ. of South Florida, Tampa (USA)
2. Univ. of Miami, FL (USA)

Organic constituents isolated from the tests (shells) of six species of core-top planktonic foraminifera, ranging in age between 2 and 4 Ka BP, consist of heterogeneous mixture of proteins and polypeptides. At least seven discrete polypeptides are present as indicated by reverse phase HPLC and by gel electrophoresis. High percentages of aspartic acid and glutamic acid characterize one class of protein, while glycine, serine, and alanine-rich proteins dominate in a second class. Similar HPLC chromatographic elution profiles are observed for all species analyzed, varying only in intensity of the peaks and in amino acid composition from species to species. The approximate molecular weights of two major fossil proteins ranged between 50,000 and 70,000 daltons. A comparison of 2-4 and 300 Ka BP samples shows that while most of the polypeptides are present in both samples, some acidic polypeptides are not present in the older sample. These data suggest that some of the acidic polypeptides may be more soluble than other fractions and are lost more quickly from the test. The remaining hydrophobic, possibly more insoluble, polypeptides may be preserved in much older speciments and may be useful in tracing phylogeny of the planktonic foraminifera. Amino acid analyses of total test extracts before and after dialysis demonstrate that some acidic amino acids, particularly aspartic acid, and possibly peptides less than 6,000-8,000 daltons are lost during dialysis. These data caution against the use of total amino acid compositions in biogeochemical studies.

• OSTI ID: 5982203
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 54:8; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AMINO ACIDS
ANIMALS
AQUATIC ORGANISMS
BIOGEOCHEMISTRY
CARBOXYLIC ACIDS
CHEMISTRY
DISSOLUTION
FORAMINIFERA
FOSSILS
GEOCHEMISTRY
INVERTEBRATES
MICROORGANISMS
MOLECULAR WEIGHT
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDES
PLANKTON
POLYPEPTIDES
PROTEINS
PROTOZOA
SARCODINA
SOLUBILITY