Open AccessBiosynthesis of antifreeze polypeptides in the winter flounder
Author(s) -
HEW Choy L.,
WANG Nam C.,
YAN Sixu,
CAI Hongyu,
SCLATER Anne,
FLETCHER Garth L.
Publication year - 1986
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1986.tb09966.x
Subject(s) - antifreeze protein , winter flounder , antifreeze , edman degradation , size exclusion chromatography , flounder , biochemistry , in vitro , chemistry , amino acid , biosynthesis , high performance liquid chromatography , chromatography , biology , peptide sequence , fish <actinopterygii> , gene , enzyme , fishery , organic chemistry
The precursor proteins for winter flounder antifreeze polypeptide (AFP) were isolated from liver using gel filtration chromatography and reverse‐phase high‐performance liquid chromatography. Two major pro‐antifreezes ( M r 5000), corresponding to the precursors for AFP‐6 and AFP‐8, were characterized by amino acid analyses and automated Edman degradation. These precursors showed significant antifreeze activity. The proantifreezes were synthesized in the liver seasonally as demonstrated by immunoblotting and in vitro liver incorporation studies. No mature AFP were detected in liver, thus indicating that the processing of pro‐antifreezes, including amidation of the C‐termini, occurred mainly in the serum. The function(s) of the prosequences, if any, remain unclear.