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Arylamine N-methyltransferase and thiol methyltransferase activities in cholestatic rat liver induced by common bile duct ligation

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Author(s)
You Hee KimIl Joo
Keimyung Author(s)
Kim, You Hee
Department
Dept. of Biochemistry (생화학)
Journal Title
Experimental and Molecular Medicine.
Issued Date
2001
Volume
33
Issue
1
Abstract
Methylation catalyzed by methyltransferases is a
major metabolic pathway for an inactivation of some
catecholamines, niacinamide as well as aliphatic
sulfhydryl drugs and toxic hydrogen sulfides. To
investigate the effects of obstructive jaundice in an
animal model, common bile duct ligation (CBDL)
was performed in the rat and enzyme activities of Sadenosyl-
L-methionine-dependent arylamine Nmethyltransferase
and thiol methyltransferase were
examined in liver cell fractions and serum for a
period of 42 d after CBDL. Both mitochondrial and
microsomal arylamine N-methyltransferase showed
significant increases in their activities between the
1st through the 7th day (P ú 0.05 to 0.001), and
between the 1st through the 28th day (P ú 0.01 to
0.001) post-ligation, although the cytosolic arylamine
N-methyltransferase activity did not show a
significant change compared to the activities from
the sham-operated control. The mitochondrial as
well as microsomal thiol methyltransferase showed
significant increases in their activities between the
1st through the 28th day (P ú 0.05 to 0.01 and P ú
0.01 to 0.001, respectively) post-ligation, although
the cytosolic thiol methyltransferase activity did not
show a significant change compared to the activities
from the sham-operated control. Arylamine N-methyltransferase
and thiol methyltransferase in the
serum from cholestatic rats also showed significant
increases in their activities between the 1st through
28th day (P ú 0.01 to 0.001), and between the 0.5th
through the 42nd day (Pú0.05 to 0.001) post-ligation
compared to the sham-operated control, respectively.
Enzyme kinetic parameters (Km and Vmax) of
hepatic membrane-bound arylamine N-methyltransferase
and thiol methyltransferase were analyzed
with the preparation from the 7th day post-ligation,
using tryptamine or 4-chlorothiophenol as substrates
and S-Adenosyl-L-[methyl-3H]methionine as co-substrate.
The results indicate that although the Km values
were about the same as the sham-operated
control, the Vmax values of both enzymes increased
significantly (Pú0.01 and 0.001, respectively). These
results suggest that the biosynthesis of arylamine
N-methyltransferase and thiol methyltransferase
have been induced in response to obstructive jaundice.
Keywords: arylamine N-methyltransferase, cholestatic
rat liver, enzyme induction, thiol methyltransferase
Keimyung Author(s)(Kor)
김여희
Publisher
School of Medicine
Citation
You Hee Kim and Il Joo. (2001). Arylamine N-methyltransferase and thiol methyltransferase
activities in cholestatic rat liver induced by common bile duct
ligation. Experimental and Molecular Medicine., 33(1), 23–28. doi: 10.1038/emm.2001.5
Type
Article
ISSN
1226-3613
DOI
10.1038/emm.2001.5
URI
https://kumel.medlib.dsmc.or.kr/handle/2015.oak/35707
Appears in Collections:
1. School of Medicine (의과대학) > Dept. of Biochemistry (생화학)
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