Biomedical subjects
Publications and source records attributed to R W Wyckoff.
1. A study has been made of the gelatins obtained by treating a number of fresh and fossil collagens with dilute formic acid. 2. Compositions of their peptides separated by filtration through polyacrylamide gels has been established. 3. Solubilization results in the freeing of much aspartic acid and less glycine, the amounts being determined for the collagens investigated.
1. Studies have been made of products obtained by treating several reptilian fossil bones with dilute formic acid. 2. Their amounts and compositions have been compared with those of similarly treated fresh and Pleistocene bones. 3. Fewer and small peptides are obtained from the older fossils but in only one instance was the composition significantly different from that of the total protein. 4. For the collagenous proteins aspartic acid was the most readily freed by hydrolysis; for these older proteins it is alanine. 5. Unlike the Pleistocene proteins, the chromatograms from these older proteins have always had peaks in the position of beta-alanine, and usually others of unidentified origin.
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More than 90% of the protein in the shells of the modern oyster, Ostrea angelica, is decomposed when shells are heated at 130 degrees for 1 week. There remains, however, a stable residue that is little changed as heating is continued for 9 weeks. This residue resembles, in both amount and composition, the material previously recovered from fossil oyster shells deposited before the Pliocene era.
Amino acid analyses have been made of the insoluble protein, soluble peptide, and free amino acid fractions isolated from a series of fossil pecten shells of ages from the Pleistocene through the Jurassic. The total amino acid content declines progressively with age of the fossil but, in contrast to oyster shells, only a small fraction of the initial protein is present in the Pleistocene and older specimens. Though the thermally less stable acids are depleted in the free acid fraction, this is not true for the insoluble proteins and peptides. Large amounts of free amino acids and peptides persist through the Pliocene, considerable quantities of peptide have been recovered from the Miocene specimens, and even the oldest fossils have retained analyzable amounts of all three fractions.
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Analyses of the protein residues recovered from fossil oyster shells of ages from the Pleistocene through the Cretaceous show substantially the same amino acids as are present in modern proteins. The amount of these residues declines sharply to the Oligocene, after which it proceeds more slowly. These older proteins contain relatively less aspartic acid and glycine than do their younger counterparts.
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