Spermidine nuclear acetylation in rat hepatocytes and in logarithmically growing rat hepatoma cells: comparison with histone acetylation.

摘要: Spermidine acetylation has been studied in nuclear homogenates and entire nuclei from rat hepatocytes hepatoma tissue culture (HTC) cells, isolated at different stages of logarithmic growth, compared to histone acetylation. Under all experimental conditions, N8-acetylspermidine was the predominant product reaction (90%). Unlike histone, spermidine HTC cell hepatocyte almost absent or strikingly reduced relative using as enzyme sources. This due lack a free minor pool spermidine, most likely lost during purification nuclei. Thus, preincubation intact presence restored activities values observed sonicates. fluctuated moderately being stimulated immediately after initiation proliferation decreasing progressively cultures reached high density. pattern corroborated that intracellular accumulation induced by culturing cells 1 mM 7-amino-2-heptanone, competitive inhibitor deacetylase. Histone growth not markedly qualitatively spermidine. Moreover, acetylations were same order magnitude those seen Finally, inhibition deacetylation had no apparent deleterious effects on growth. It remains be determined whether step is higher physiological importance, particular, discussed turnover.