Kit Y Y, Kuligina E V, Richter V A, Stoika R S
Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv.
Ukr Biokhim Zh (1999). 2007 May-Jun;79(3):55-60.
It was found that milk of clinical healthy women contains sIgA possessing high affinity for the mammalian thymus DNA and DNA-hydrolyzing activity (sIgA-abzymes). Here we present data that such sIgA-abzymes, purified by sequential chromatography on DEAE-fractogel, heparin-sepharose, DNA-cellulose and followed by gel-filtration, are also able to hydrolyse total RNA from E. coli better than plasmid DNA. Besides, such sIgA-abzymes effectively cleaved 18S and 28S ribosomal RNA isolated from human A549 cells. It is noteworthy that the nuclease activity of sIgA-abzymes was significantly inhibited by ATP, while dATP had no effect on it. A potential role of the ribonuclease activity of sIgA-abzymes present in human milk is discussed.
研究发现，临床健康女性的乳汁中含有对哺乳动物胸腺DNA具有高亲和力且具有DNA水解活性的分泌型免疫球蛋白A（sIgA - 抗体酶）。在此我们展示的数据表明，通过先后在DEAE - fractogel、肝素 - 琼脂糖、DNA - 纤维素上进行层析，随后进行凝胶过滤纯化得到的此类sIgA - 抗体酶，相较于质粒DNA，能更好地水解大肠杆菌的总RNA。此外，此类sIgA - 抗体酶能有效切割从人A549细胞中分离出的18S和28S核糖体RNA。值得注意的是，ATP能显著抑制sIgA - 抗体酶的核酸酶活性，而dATP对其无影响。本文讨论了人乳中存在的sIgA - 抗体酶的核糖核酸酶活性的潜在作用。
