IN VITRO STUDIES ON THE BIOSYNTHESIS OF UBIQUINONE

1960 ◽  
Vol 38 (10) ◽  
pp. 1105-1115 ◽  
Author(s):  
W. E. J. Phillips

Radioactive ubiquinone can be isolated from rat liver following intraperitoneal injections of C14-acetate or mevalonic acid. No detectable amount of radioactive ubiquinone could be isolated from liver homogenates, liver slices, or intestinal mucosa incubated in vitro with C14-acetate or mevalonic acid. The possible requirement of isolated tissues for an exogenous factor is discussed.

1960 ◽  
Vol 38 (1) ◽  
pp. 1105-1115 ◽  
Author(s):  
W. E. J. Phillips

Radioactive ubiquinone can be isolated from rat liver following intraperitoneal injections of C14-acetate or mevalonic acid. No detectable amount of radioactive ubiquinone could be isolated from liver homogenates, liver slices, or intestinal mucosa incubated in vitro with C14-acetate or mevalonic acid. The possible requirement of isolated tissues for an exogenous factor is discussed.


1966 ◽  
Vol 44 (12) ◽  
pp. 1615-1624 ◽  
Author(s):  
W. E. J. Phillips ◽  
M. Hidiroglou ◽  
G. Hatina

Mevalonic acid was incorporated into the ubiquinone and sterol fractions of rat-liver homogenates. The incorporation of mevalonate was increased approximately 10-fold in the total non-saponifiable matter including sterol by use of the in vitro homogenate system as compared with intact rats. The incorporation into the ubiquinones was decreased. The addition of potential ring precursors, p-hydroxybenzoic acid, L-phenylalanine, or L-tyrosine to the homogenate system did not increase incorporation of mevalonate into ubiquinone.Incubation of subcellular fractions from rat-liver homogenates demonstrated that supernate plus either mitochondria or microsomes were necessary for the biosynthesis of ubiquinone.


1966 ◽  
Vol 44 (1) ◽  
pp. 129-140 ◽  
Author(s):  
Bernard Rubenstein ◽  
David Rubinstein

The ability of liver slices from rats fasted 48 hours to esterify palmitate-1-14C is about half of that of slices from fed animals. The same effect can be observed in homogenates of liver freed of nuclei, either with or without mitochondria. In both preparations, the synthesis of triglycerides is chiefly affected. The decrease in esterification by homogenate supernatants containing microsomes from fasted animals can be overcome by using increased amounts of ATP or an ATP generator and NaF in the incubation medium. The ATPase responsible for the higher ATP requirement in liver homogenates from fasted animals is Mg++-dependent. Higher concentrations of ATP inhibit esterification by mitochondrial preparations. Incorporation of both palmitate-9-10-3H and of glycerol-1-3-14C is reduced to the same extent for each compound in slices from fasting animals. Glycerol kinase and α-glycerophosphate dehydrogenase are both unaffected by 48 hours' fasting. It is concluded that the decrease in ATP from the activation of ATPase is responsible for the decreased esterification in the intact cell.


2008 ◽  
Vol 46 (01) ◽  
Author(s):  
F Moriconi ◽  
H Christiansen ◽  
H Christiansen ◽  
N Sheikh ◽  
J Dudas ◽  
...  

Xenobiotica ◽  
2003 ◽  
Vol 33 (5) ◽  
pp. 511-527 ◽  
Author(s):  
C. Meredith ◽  
M. P. Scott ◽  
A. B. Renwick ◽  
R. J. Price ◽  
B. G. Lake
Keyword(s):  

Life Sciences ◽  
1986 ◽  
Vol 38 (24) ◽  
pp. 2231-2238 ◽  
Author(s):  
Shinya Kobayshi ◽  
Yan Gao ◽  
Richard L. Ong ◽  
Constance S. Pittman

1977 ◽  
Vol 26 (11) ◽  
pp. 1043-1049 ◽  
Author(s):  
Ronald T. Coutts ◽  
Susan H. Kovach
Keyword(s):  

1962 ◽  
Vol 203 (4) ◽  
pp. 687-689 ◽  
Author(s):  
J. C. Penhos ◽  
M. E. Krahl

Slices prepared from livers of bull frogs ( Rana catesbiana), pancreatectomized and/or hypophysectomized 7 days before, were incubated 2 hr in frog Ringer-bicarbonate solution at 25 C. Incorporation of leucine-1-C14 into protein was subnormal in the pancreatectomized series. The addition of insulin in vitro, with glucose also present in the medium, produced a significant ( P < 0.01) stimulation of amino acid incorporation in the following series: livers from normal fed animals; livers from animals pancreatectomized 7 days before; and livers from animals pancreatectomized and hypophysectomized 7 days before. Neither insulin nor glucose alone gave a significant effect. These results therefore confirm and extend those obtained with rat liver slices showing that insulin can stimulate amino acid incorporation into protein when added directly to liver. The effect is relatively greatest with livers from animals pancreatectomized 7 days before; the insulin effect does not depend on the presence of the pituitary, as it is obtainable with livers from animals hypophysectomized and pancreatectomized 7 days previously.


Sign in / Sign up

Export Citation Format

Share Document