Spermidine is bound to a unique protein in early sea urchin embryos.
Spermidine is rapidly taken up and becomes bound to protein during the very early hours of sea urchin embryogenesis. During the first 6 hr after fertilization of freshly obtained sea urchin eggs (Strongylocentrotus purpuratus), which are incubated in the presence of exogenous [3H]-spermidine, up to 7% of the total cell-associated spermidine appears uniquely as spermidine bound in macromolecular form. This unique protein containing spermidine migrates as a single radioactive band in gel electrophoresis. It has a Mr of approximately equal to 30,000 and is readily distinguishable from the protein initiation factor eIF-4D, which has a Mr of 18,000, the only other identifiable protein known to date to be posttranslationally modified by polyamines.
D000818:Animals; D002352:Carrier Proteins / Q000302:isolation & purification*; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D008970:Molecular Weight; D010063:Ovum / Q000378:metabolism; D014176:Protein Biosynthesis; D012617:Sea Urchins; D013095:Spermidine / Q000378:metabolism*; D014316:Tritium
D002352:Carrier Proteins; D014316:Tritium; D013095:Spermidine