. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EVOLUTION OF VERTEBRATE PLASMA PROTEINS 277 1 2345678. FIGURE 5. SDS-polyacrylamide () gel electrophoresis (reducing conditions) of lamprey plasma and plasma materials. I, purified lamprey transferrin; 2, reference substances (chymotrypsinogen, myoglo- bin and lysozyme); 3, lamprey fibrinogen; 4, lamprey albumin; 5 and 6, lamprey plasma; 7, high density ultracentrifugate (HDL layer); 8, lipoprotein "cake" from ultracentrifuged lamprey plasma (from Pontes etai, 1987). eins, the high rate of sequence change in th
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EVOLUTION OF VERTEBRATE PLASMA PROTEINS 277 1 2345678. FIGURE 5. SDS-polyacrylamide () gel electrophoresis (reducing conditions) of lamprey plasma and plasma materials. I, purified lamprey transferrin; 2, reference substances (chymotrypsinogen, myoglo- bin and lysozyme); 3, lamprey fibrinogen; 4, lamprey albumin; 5 and 6, lamprey plasma; 7, high density ultracentrifugate (HDL layer); 8, lipoprotein "cake" from ultracentrifuged lamprey plasma (from Pontes etai, 1987). eins, the high rate of sequence change in these materials makes it difficult to prove a case for common ancestry. TRANSFERRIN Transferrin, the iron transport protein, is well known to be a major component in the blood plasmas of all vertebrates. It is also common knowledge that among all classes of vertebrates, including cyclostomes, the molecule is an internal dimer with two iron-binding sites. One of our graduate students, Barbara Evans, purified lamprey transferrin, and, together with Dr. Kenneth Watt, determined the amino-terminal 47 amino acids (Evans et al, 1984). Attempts to clone the message were unsuccessful, however. We had hoped to shed more light on when the tandem duplication occurred that led to the double-sized molecule. In the meantime, an iron-binding protein has been found in the ascidian Pyura stolonifera that is half the size of vertebrate transfer- rin (Huebers et al, 1984). It will be of great interest to see if the sequence of the ascidian protein is recognizably homologous with the vertebrate molecule. COMPUTER SEARCHING Up to this point, I have been discussing the evolution of vertebrate plasma pro- teins on the basis of comparisons of proteins as they exist in contemporary mammals. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original wor
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
