ABSTRACT
WefoundthatretinoylationingrowingHL60culturesoccursontheproteinof newlyformedcellsandontheproteininpreexistingcells(15).Wemeasured retinoylationinthepresenceofcycloheximidetolearnifretinoylationoccursin nongrowingcellsorifitrequiresturnoverorinductionoftheproteinsubstrate. With3.6J.!Mcycloheximidethereisgreaterthan86%inhibitionofprotein synthesis(31)andnocellgrowthfor48hr.Retinoylationisveryrapidinitially andthencontinuesatalinearrateforatleast48hr.Thelevelofretinoylation (fmol/106cells)at48hrinthepresenceofcycloheximidewasaboutthesameas thatseenat48hringrowingcultures(17)andindicatesthatretinoylationis primarilyamodificationofpreformedproteins.
