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Purification of Somatostatin from Frog Brain: Coisolation with Retinal Somatostatin‐Like Immunoreactivity
Author(s) -
Takami Mimi,
Reeve Joseph R.,
Hawke David,
Shively John E.,
Basinger Scott,
Yamada Tadataka
Publication year - 1985
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1985.tb10545.x
Subject(s) - somatostatin , retinal , edman degradation , retina , biology , biochemistry , neurotransmitter , amino acid , peptide sequence , medicine , chemistry , endocrinology , neuroscience , receptor , gene
Somatostatin‐like immunoreactivity (SLI) was purified from frog brain and retina, and the structure of the brain peptide was determined. Frog brain (101 g) and retinal (45 g) tissues were extracted with 3% acetic acid, yielding 9.6 and 0.44 nmol of SLI, respectively. SLI was further purified by chromatography on a somatostatin immunoaffinity column followed by sequential application to reverse‐phase C‐18 HPLC columns. The brain and retinal peptides, purified roughly 100,000‐fold with net yields of 7.5 and 2.3%, respectively, appeared identical in the final steps of purification. The amino acid sequence of brain SLI, as determined by a gas‐phase automated Edman degradation technique, was as follows: Ala‐Gly (Cys)‐Lys‐Asn‐Phe‐Phe‐Trp‐Lys‐Thr‐Phe‐Thr‐Ser‐ (Cys). Our data indicate that despite structural variations in somatostatins of other lower vertebrates, the amino acid sequence of frog brain and, by deduction, retinal SLI is identical to that of somatostatin tetradecapeptide. These findings support the physiological relevance of studies directed at elucidating the neurotransmitter function of somatostatin using the well‐established models of frog brain and retina.