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생체막 구조의 변화에 따른 5'-Nucleotidase 활성의 변화
Changes in the Activites of 5'-Nucleotidase relating to the Structural Change of the Membrane

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Authors
김철규; 최한웅; 정홍근; 이기영
Issue Date
1979-12
Publisher
서울대학교 의과대학
Citation
Seoul J Med 1979;20(3):279-288
Abstract
Assay of 5'-nucleotidase is a biochemical tool to
identify the plasma membrane in subcellular fractlonationc
fy-Nucleotidase was reported to be activated
by Mg" ion but the authors observed that the
degree of activation depended on the structural
state of the plasma membrane. This experiment
was performed to study further in detail the change
in 5'-nucleotidase activity relating to the chan·
ge of the structural state of the plasma membrane.
The results obtained are summarized as follows:
1. Rat livers were homogenized in O. 25M sucrose
and the homogenate was fractionated into 2000 X g
fraction, mitochondrial fraction and microsomal
fraction according to the particle size of the plasma
membrane. The activation effect of Mg" ions on
5'-nucleotidase was tested on each fraction. The 'effect was most pronounced in the microsomal frac-
lion and the most effective concentration of Mg"
'ions was 10mM.
2. Microsomal vesicles increased in size in the
presence of lOmM Mg" ions in the assay system of
'5'-nucleotidase, which was confirmed by Tyndall
effect and electron microscopy.
3. Microsomal vesicles were coagulated in the
presence of 10mM Ca* ions in the assay system of
'5'-nucleotidase, which was confirmed by Tyndall
. effect and electron microscopy and Ca" ions inhibited
5'-nucleotidase about 30% at the concentration
'of 10mM.
4. From Tyndall effect of the microsomal vesicles
it was shown that the vesicles were slowly
enlarged in the hypotonic assay system at 30'C,
but the vesicles did not increase in size at 16'C.
5. When the activities of 5'-nucleotidase were
'measured by starting the enzyme reaction with the
.substrate, the activities of the enzyme were increased
with increasing incubation period of the en'
zyme preparation in the enzyme assay buffer at 30'C
'before addition of the substrate. From this result
it is concluded that the activities of 5' -nucleotidase
'should be measured by starting the enzyme reaction
with the enzyme preparation.
6. The activity of 5'-nucleotidase in the micro'
somal fraction was increased with aging the mi-
crosomal fraction in the refrigerator at 4 'C, which
was accompanyed by the increase in lipid peroxide.
Thus the increase in the enzyme activity of the
microsomal fraction was about 40% after 4 days'
aging. The activation effect of Mg" ions on 5'-nu.
cleotidase was decreased with aging.
Language
Korean
URI
http://hdl.handle.net/10371/7232
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Appears in Collections:
College of Medicine/School of Medicine (의과대학/대학원)Dept. of Medicine (의학과)The Seoul Journal of MedicineThe Seoul Journal of Medicine Vol. 20 No.4 (1979)
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