Endogenous oligonucleotides of human milk and their possible biological function. |
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| Authors: | Y Y Kit E V Kuligina A M Onishchenko L V Yurchenko I V Romannikova V A Richter V V Vlassov |
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| Institution: | Novosibirsk Institute of Bioorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia. kit@niboch.nsc.ru |
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| Abstract: | Oligonucleotides (ON) 4 to 60 nucleotides in length were isolated by ion-exchange chromatography on a column with Fractogel TSK DEAE-650 (M) from human milk which was hydrolyzed with proteinase K. ON from 60 to 16 nucleotides were degraded by RNase A but were resistant to DNase I, and, thus, they were ribooligonucleotides. In the presence of gamma-32P]ATP, ON and heparin inhibited the phosphorylation of 38- and 20-kD milk proteins and failed to affect the phosphorylation of a 76-kD protein. Human milk is believed to contain polyanion-dependent and polyanion-independent protein kinases. The influence of the ON on the activity of the cytotoxic fraction of human milk alpha-lactalbumin towards human mammary gland carcinoma MCF-7 cells was studied. The ON inhibited the cytostatic and cytotoxic effects of alpha-lactalbumin. Synthetic oligonucleotides and heparin had similar effects. The endogenous ON are suggested to be involved in the regulation of cytotoxic activity of human milk. |
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