scholarly journals The intracellular location of pyruvate carboxylase, citrate synthase and 3-hydroxyacyl-CoA dehydrogenase in lactating rat mammary gland

1978 ◽  
Vol 171 (1) ◽  
pp. 273-275 ◽  
Author(s):  
D J Taylor ◽  
B Crabtree ◽  
G H Smith

The intracellular location of pyruvate carboxylase (EC 6.4.1.1), citrate synthase (EC 4.1.3.7) and 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) in rat mammary gland was investigated by using a fractional-extraction technique. The results indicate a mitochondrial location for all three enzymes.

1969 ◽  
Vol 112 (3) ◽  
pp. 293-301 ◽  
Author(s):  
Bilquis Gul ◽  
R. Dils

1. Activities of glucose 6-phosphate dehydrogenase (EC 1.1.1.49), 6-phosphogluconate dehydrogenase (EC 1.1.1.44), isocitrate dehydrogenase (EC 1.1.1.42), malate dehydrogenase (EC 1.1.1.37), malate dehydrogenase (decarboxylating) (EC 1.1.1.40), and pyruvate carboxylase (EC 6.4.1.1) were determined in subcellular fractions of mammary gland from rabbits during pregnancy, at different stages of lactation and during weaning. The results were compared with those obtained in similar experiments with rat mammary gland. 2. Three bases of expression of the activity of enzymes in the particle-free supernatant fraction of mammary gland were compared. During lactation, activity expressed per mg. of particle-free supernatant protein (uncorrected for milk protein) correlated well with that expressed per μg. of DNA phosphorus. The disadvantages of expressing activities per g. wet wt. are discussed. 3. The major differences between the two tissues were: (a) neither malate dehydrogenase (decarboxylating) nor a soluble form of pyruvate carboxylase could be detected in rabbit mammary gland at any stage of the lactation cycle; (b) isocitrate dehydrogenase increased in activity during lactation in rabbit mammary gland, but not in that of the rat. 4. Pyruvate carboxylase in the mitochondrial fraction of rabbit mammary gland, and in both the mitochondrial and the soluble fractions of rat mammary gland, did not change in activity during lactation. 5. For each tissue, the NADP-dependent dehydrogenases studied had a high activity at all stages of the lactation cycle compared with the rate of fatty acid synthesis at mid-lactation. The significance of these results is discussed with respect to the supply of NADPH via NADH.


1969 ◽  
Vol 111 (3) ◽  
pp. 263-271 ◽  
Author(s):  
Bilquis Gul ◽  
R. Dils

1. Pyruvate carboxylase [pyruvate–carbon dioxide ligase (ADP), EC 6.4.1.1] was found in cell-free preparations of lactating rat and rabbit mammary glands, and optimum assay conditions for this enzyme were determined. 2. Subcellular-fractionation studies with marker enzymes showed pyruvate carboxylase to be distributed between the mitochondrial and soluble fractions of lactating rat mammary gland. Evidence is presented that the soluble enzyme is not an artifact due to mitochondrial damage. 3. In contrast, pyruvate carboxylase in lactating rabbit mammary gland is confined to the mitochondrial fraction. 4. The final product of pyruvate carboxylase action in the mitochondrial and particle-free supernatant fractions of lactating rat mammary gland was shown to be citrate. 5. The effects of freeze-drying, ultrasonic treatment and freezing-and-thawing on the specific activity of mitochondrial pyruvate carboxylase were investigated.


Endocrinology ◽  
1998 ◽  
Vol 139 (2) ◽  
pp. 753-764 ◽  
Author(s):  
Antigone Sourla ◽  
Céline Martel ◽  
Claude Labrie ◽  
Fernand Labrie

BMC Cancer ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Lina Ding ◽  
Yang Zhao ◽  
Christopher L Warren ◽  
Ruth Sullivan ◽  
Kevin W Eliceiri ◽  
...  

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