Modulation of partially purified rat liver mitochondrial carbamoyl phosphate synthetase I using two glutamic acid analogues
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Date
2014-10Author
Machua, Shadrack K
Mukuria, Joseph C
Ngure, Raphael M
Language
enMetadata
Show full item recordAbstract
Mitochondrial
c
arbamoyl ph
osphate synthetase I
(CPS I)
i
s
the first enzyme involved in urea
biosynthesis
in ureotelic mammals
and has
an absolute requirement for N
-
acetyl
-
L
-
glutamate (NAG)
or
N
-
carbamyl
-
L
-
glutamate (NCLG) in absence of NAG
as its allosteric modulator.
To
investigate
effect of
diet on
CPS
I
acti
vation
,
three
male albino rats were maintained under normal laboratory diet
(control)
and another
three
on high protein egg white diet for 10 days
.
The percentage mean weight gain for the
normal diet was 6.4
% while the percentage mean weight loss for the
high protein diet group 18.6
%.
The
rats were sacrificed and
CPS I isolated from the liver mitochondria through differential centrifugation
and partially purified by ammonium sulphate precipitation, gel filtration on Sephadex G
-
200 and native
polyacrylamid
e gel electrophoresis (PAGE).
Lactate dehydrogenase
-
pyruvate kinase (LDH
-
PK) coupled
assay system was devised to determine the effect of NAG and its structural
analogue
NCLG in the
activation of CPS I from rats fed on the two diets.
CPS I activity of 268.1
6
nmol/min/mg in the control
group doubled to 553.86
nmol/min/mg in rats fed on high protein.
An initial velocity of CPS I of 3.07
nmol/min/mg was observed when activated by 0.57 mM NAG and a lowered activity of 2.2 nmol/min/mg
when replaced with 0.57 mM N
CLG.
Both NAG and NCLG activated CPS I at all concentrations tested in
the assay system devised with improved activity seen when CPS I activity was measured in presence of
NAG
URI
http://www.uniqueresearchjournals.org/urjbb/pdf/2014/October/Shadrack%20et%20al..pdfhttp://hdl.handle.net/11295/77629
Citation
Machua, S. K., Mukuria, J. C., Ngure, R. M., & Gitu, P. M. (2014). Modulation of partially purified rat liver mitochondrial carbamoyl phosphate synthetase I using two glutamic acid analogues.Publisher
University of Nairobi