scholarly journals Genetic control of metabolism: enzyme studies of the obese and adipose mutants in the mouse

1972 ◽  
Vol 20 (1) ◽  
pp. 51-64 ◽  
Author(s):  
Grahame Bulfield
Keyword(s):  
Enzyme Activity ◽  
Malate Dehydrogenase ◽  
Primary Lesion ◽  
Gas Liquid Chromatography ◽  
Wild Type ◽  
Atp Citrate Lyase ◽  
Citrate Lyase ◽  
Lyase Activity ◽  
Metabolism Enzyme ◽  
Pheno Type

SUMMARYThe activity of several enzymes has been determined in the livers of homozygous obese and adipose mice, their normal litter-mates, and phenocopies induced in normal mice by aurothioglucose (ATG) injections.Obese, adipose and ATG mice had higher activities of ATP citrate lyase, malic enzyme (NADP malate dehydrogenase) and pyruvate kinase than normal mice. Heterozygote activities are indistinguishable from wild-type. There was no difference between normal and fat litter-mates in the activity of malate dehydrogenase (NAD-linked), lactate dehydrogenase, isocitrate dehydrogenase and fumarase.Crosses between mice doubly heterozygous for roth the ad and ob genes produced offspring that were only ‘fat’ or ‘normal’ and no offspring could be phenotypically recognized as the double mutant, either physically or in terms of ATP citrate lyase activity.Gas–liquid chromatography of the fatty acids of the depot fat showed no differences between any of the types of litter-mate.The alterations found in enzyme activity in obese and adipose mice are compared to several other enzyme activity differences reported in the literature for obese mice. These are discussed in relation to genetical criteria that may be estarlished to assess, from quantitative data, whether an enzyme is the site of the primary lesion in a mutant pheno-type. Some general observations are made on genetics and the control of metabolism.

Enzyme Activities of NADPH-Forming Metabolic Pathways in Normal and Leukemic Leukocytes

1975 ◽  
Vol 21 (7) ◽  
pp. 880-883 ◽  
Author(s):  
Francesco Belfiore ◽  
Vito Borzi ◽  
Luigi Lo Vecchio ◽  
Elena Napoli ◽  
Agata M Rabuazzo
Keyword(s):  
Malate Dehydrogenase ◽  
Metabolic Pathways ◽  
Normal Subjects ◽  
Atp Citrate Lyase ◽  
Phosphogluconate Dehydrogenase ◽  
Myelocytic Leukemia ◽  
Citrate Lyase ◽  
Enzymatic Characteristic ◽  
I Cells ◽  
Low Activity

Abstract With respect to the enzymes of NADPH-forming metabolic pathways in human leukocytes: (a) Glucose-6phosphate dehydrogenase and phosphogluconate dehydrogenase (decarboxylating) were less active in leukocytes (mostly myeloblasts) from eight patients with acute myeloblastic leukemia (I) than in leukocytes (mostly granulocytes) from 16 normal subjects (II) or 16 patients with chronic myelocytic leukemia (III). (b) Of the enzymes of the citrate cleavage pathway, ATP citrate lyase and malate dehydrogenase (decarboxylating) (NADP+) were virtually absent in the cells studied. (c) Isocitrate dehydrogenase (NADP+), aspartate aminotransferase, and alanine aminotransferase, which, together with the much more active malate dehydrogenase, constitute a newly proposed NADPH-forming metabolic cycle, showed a higher activity in I than in II or III, and therefore could compensate, as concerns NADPHgeneration, for the low activity of pentose cycle dehydrogenases. We are not sure whether the enzymatic characteristic of I cells is attributable to their immaturity or to their leukemic nature.

Genetic Manipulation of Key Photosynthetic Enzymes in the C4 Plant Flaveria bidentis

1997 ◽  
Vol 24 (4) ◽  
pp. 477 ◽  
Author(s):  
Robert T. Furbank ◽  
Julie A. Chitty ◽  
Colin L.D. Jenkins ◽  
William C. Taylor ◽  
Stephen J. Trevanion ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Malate Dehydrogenase ◽  
Genetic Manipulation ◽  
Photosynthetic Performance ◽  
Covalent Modification ◽  
Wild Type ◽  
Bisphosphate Carboxylase ◽  
Photosynthetic Enzymes ◽  
Flaveria Bidentis

The NADP-malic enzyme type C4 dicot Flaveria bidentis (L.) Kuntze was transformed with antisense and cosense gene constructs that resulted in specific decreases in single photosynthetic enzymes. The enzymes targeted were ribulose-1,5-bisphosphate carboxylase/oxygenase [EC 4.1.1.39] (Rubisco), pyruvate, Pi dikinase [EC 2.7.9.1] (PPDK) and NADP malate dehydrogenase [EC 1.1.1.82] (NADP-MDH). These enzymes were chosen as targets because they have low activity compared to photosynthetic rates (Rubisco), are subject to complex covalent regulation (NADP-MDH), or both (PPDK). T1 progeny of a number of lines of these transformants were examined for the effects of these gene constructs on enzyme levels and photosynthetic performance. Rubisco antisense transformants expressing between 15 and 100% of wild-type enzyme activity were obtained. Pyruvate, Pi dikinase antisense lines were obtained with 40–100% wild-type levels. NADP malate dehydrogenase sense constructs caused a co-suppression of enzyme activity with some lines containing less than 2% of wild- type activity. Under saturating illumination, the control coefficients for these enzymes were determined to be up to 0.7 for Rubisco, 0.2–0.3 for PPDK and effectively zero for NADP-MDH. The implications of these observations for the regulation of photosynthetic flux and metabolism in C4 plants and the role of regulation by covalent modification are discussed.

scholarly journals Changes in activity of some enzymes involved in glucose utilization and formation in developing rat liver

1968 ◽  
Vol 106 (2) ◽  
pp. 321-329 ◽  
Author(s):  
R. G. Vernon ◽  
D G Walker
Keyword(s):  
Malate Dehydrogenase ◽  
Rat Liver ◽  
Postnatal Period ◽  
Supernatant Fraction ◽  
Atp Citrate Lyase ◽  
Carboxylase Activity ◽  
Phosphogluconate Dehydrogenase ◽  
Citrate Lyase ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Developing Rat

1. The activities of some enzymes involved in both the utilization of glucose (pyruvate kinase, ATP citrate lyase, NADP-specific malate dehydrogenase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and NADP-specific isocitrate dehydrogenase, all present in the supernatant fraction of liver homogenates) and the formation of glucose by gluconeogenesis (glucose 6-phosphatase in the whole homogenate and fructose 1,6-diphosphatase, phosphopyruvate carboxylase, NAD-specific malate dehydrogenase and fumarase in the supernatant fraction) have been determined in rat liver around birth and in the postnatal period until the end of weaning. 2. The activities of those enzymes involved in the conversion of glucose into lipid are low during the neonatal period and increase with weaning. NADP-specific malate dehydrogenase first appears and develops at the beginning of the weaning period. 3. The marked increase in cytoplasmic phosphopyruvate carboxylase activity at birth is probably the major factor initiating gluconeogenesis at that time. 4. The results are discussed against the known changes in dietary supplies and the known metabolic patterns during the period of development.

INDUCTION BY GONADAL HORMONES OF HEPATIC LIPOGENIC ENZYME ACTIVITY IN IMMATURE PULLETS

1974 ◽  
Vol 61 (1) ◽  
pp. 29-43 ◽  
Author(s):  
D. BALNAVE ◽  
J. PEARCE
Keyword(s):  
Enzyme Activity ◽  
Corn Oil ◽  
Specific Activity ◽  
Liver Lipid ◽  
Lipogenic Enzyme ◽  
Atp Citrate Lyase ◽  
Liver Lipid Content ◽  
Hormone Administration ◽  
Citrate Lyase ◽  
Specific Activities

SUMMARY The effect of gonadal hormone administration on hepatic lipogenic enzyme activity, and some physiological parameters was investigated in immature pullets. Pullets (aged 4 weeks) were allocated to treatment groups and received intramuscular injections of oestradiol, testosterone, progesterone or oestradiol + testosterone (all in 0·3 ml corn oil) or corn oil alone (control group). There was no evidence of any hormone-induced changes in the specific activity of hepatic ATP-citrate lyase 1, 3, 6 and 12 h after hormone administration. NADP-malate dehydrogenase exhibited significant variations in specific activity over this period of time and it is probable that these changes reflected an increased requirement for NADPH for synthetic purposes in hormone-treated birds. The effect of 1, 2, 4 and 9 days of hormone administration was also investigated. In testosterone-treated birds there were significant increases in the specific activities of both lipogenic enzymes after 1 day of hormone treatment whereas for birds receiving oestradiol the maximum specific activities were found on the second day. Similarly, the liver lipid content of oestradioltreated birds showed a substantial increase on day 2. After 9 days of hormone administration no significant differences in the specific activity of ATP-citrate lyase were observed between treatments but the specific activity of NADP-malate dehydrogenase was significantly reduced in oestradiol- or mixed hormone-treated birds; it is possible that the reduced enzyme activity is associated with a reduced requirement for NADPH and in this connexion there were no further increases in liver lipid content or liver weight after 4 days of hormone administration. The liver RNA:DNA ratio tended to be greatest in birds receiving oestradiol or oestradiol + testosterone. Studies utilizing inhibitors of RNA and protein synthesis showed that such compounds abolished the increases in lipogenic enzyme activity following hormone administration suggesting that these increases were hormone-induced effects. These results are discussed in relation to the effects of the various hormones on liver lipid metabolism and also in relation to the situation in the mature laying hen.

ATP Citrate Lyase Activity in the Liver of Newborn Lambs

1970 ◽  
Vol 67 (5) ◽  
pp. 727-729 ◽  
Author(s):  
MICHIKO MURAMATSU ◽  
KAICHI AMBO ◽  
TSUNEYUKI TSUDA
Keyword(s):  
Atp Citrate Lyase ◽  
Citrate Lyase ◽  
Lyase Activity

Urinary citrate excretion in patients with renal stone: roles of leucocyte ATP citrate lyase activity and potassium salts therapy

2002 ◽  
Vol 325 (1-2) ◽  
pp. 71-78 ◽  
Author(s):  
Piyaratana Tosukhowong ◽  
Sombat Borvonpadungkitti ◽  
Vitoon Prasongwatana ◽  
Kriang Tungsanga ◽  
Srisakul Jutuporn ◽  
...  
Keyword(s):  
Renal Stone ◽  
Potassium Salts ◽  
Atp Citrate Lyase ◽  
Citrate Lyase ◽  
Lyase Activity ◽  
Urinary Citrate

scholarly journals An investigation of lipogenic and glycolytic enzyme activity in the liver of sexually immature and mature domestic fowl

1971 ◽  
Vol 123 (5) ◽  
pp. 717-719 ◽  
Author(s):  
J. Pearce
Keyword(s):  
Enzyme Activity ◽  
Significant Variation ◽  
Egg Production ◽  
Liver Lipid ◽  
Laying Hen ◽  
Glycolytic Enzyme ◽  
Egg Laying ◽  
Atp Citrate Lyase ◽  
Liver Lipid Content ◽  
Citrate Lyase

In the non-laying pullet and the cockerel it was observed that there was no significant variation in the activities of ATP citrate lyase and `malic' enzyme whereas in the laying hen there was a significantly greater activity of both these enzymes. Parallel increases in liver lipid content in the laying hen were also observed. Three glycolytic enzymes, phosphofructokinase, fructose diphosphate aldolase and pyruvate kinase, did not exhibit any significant variation in enzyme activity with the onset of egg laying. These results are discussed in relation to the hormonal status of the birds and also the demands of egg production for lipid.

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