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KMID : 0382619900100020716
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Hanyang Journal of Medicine
1990 Volume.10 No. 2 p.716 ~ p.725
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Substrate Specificity and Mechanism of Action of Neutral RNases in Osteosarcoma Tissue
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Lee Kwang-Hyun
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Abstract
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Neutral RNase in osteosarcoma tissue were isolated and fractionated with ion exchange resin chromatographies. The substrate specificity of the neutral ribonuclease(RNase)thus isolated was determined using homo- and hetero-polyribonucleotides as substrate so as to investigate the mechnism of action of the neutral RNase in osteosarcoma tissue.
1. The activity of neutral RNase measured with polyribocytidylate (poly C) as substrate was greatly increased in the central part of osteosarcoma lesion as compared with that in noraml (control) tissue of the same case.
2. DEAE-cellulose column chromatography of neutral RNase in osteosarcoma tissue revealed the presence of two neutral RNases specific to the osteosarcoma, disappearance of two enzymes present in contral bone tissue and activation of three enzvmes in the osteosarcoma tissue.
3. DEAE-cellulose peak V neutral RNase was further separated by a phosphocellulose column chromatography into three peaks, of which two of them appeared to be specific to osteosarcoma.
4. The activity of neutral RNase in osteosarcoma tissue was greater toward C-C and C-A linkage and the activity was decreased toward C-I, C-U and U-U linkages in order. Little activity was observed toward A-A and G-G linkages. The substrate specificity of the neutral RNase isolated from osteosarcoma tissue was not identical, but slightly different from that from control bone tissue.
The results obtained from the present study indicated that neutral RNase in osteosarcoma tissues was present in the form of multiple isozymes, more than four neutral RNase were found to be specific to osteosarcoma and two enzymes present in control tissue disap-peared from the osteosarcoma tissue, suggesting the multifunctional roles of RNases in tumor tissues.
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KEYWORD
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