scholarly journals Proportional activities of glycerol kinase and glycerol 3-phosphate dehydrogenase in rat hepatomas

1975 ◽  
Vol 148 (3) ◽  
pp. 545-550 ◽  
Author(s):  
J W Harding ◽  
E A Pyeritz ◽  
H P Morris ◽  
H B White
Keyword(s):  
Malic Enzyme ◽  
Acyl Carrier Protein ◽  
Fatty Acid Synthetase ◽  
Glycerol Kinase ◽  
Carrier Protein ◽  
Strongly Correlated ◽  
Single Exception ◽  
Morris Hepatoma ◽  
Highly Correlated ◽  
Glycerol 3 Phosphate Dehydrogenase

The activities of glycerol 3-phosphate dehydrogenase (EC 1.1.1.8), glycerol kinase (EC 2.7.1.30), lactate dehydrogenase (EC 1.1.1.27), “malic’ enzyme (L-malate-NADP+ oxidoreductase; EC 1.1.1.40) and the beta-oxoacyl-(acyl-carrier protein) reductase component of the fatty acid synthetase complex were measured in nine hepatoma lines (8 in rats, 1 in mouse) and in the livers of host animals. With the single exception of Morris hepatoma 16, which had unusually high glycerol 3-phosphate dehydrogenase activity, the activities of glycerol 3-phosphate dehydrogenase and glycerol kinase were highly correlated in normal livers and hepatomas (r = 0.97; P less than 0.01). The activities of these two enzymes were not strongly correlated with the activities of any of the other three enzymes. The primary function of hepatic glycerol 3-phosphate dehydrogenase appears to be in gluconeogenesis from glycerol.

scholarly journals Role of glycerol 3-phosphate dehydrogenase in glyceride metabolism. Effect of diet on enzyme activities in chicken liver

1975 ◽  
Vol 146 (1) ◽  
pp. 223-229 ◽  
Author(s):  
J W Harding ◽  
E A Pyeritz ◽  
E S Copeland ◽  
H B White
Keyword(s):  
Lactate Dehydrogenase ◽  
High Fat Diet ◽  
Acyl Carrier Protein ◽  
Fatty Acid Synthetase ◽  
Carrier Protein ◽  
High Fat ◽  
Carbohydrate Diet ◽  
Metabolic Role ◽  
Glycerol 3 Phosphate Dehydrogenase

1. The metabolic role of hepatic NAD-linked glycerol 3-phosphate dehydrogenase (EC 1.1.1.8) was investigated vis-a-vis glyceride synthesis, glyceride degradation and the maintainence of the NAD redox state. 2. Five-week-old chickens were placed on five dietary regimes: a control group, a group on an increased-carbohydrate-lowered-fat diet, a group on a high-fat-lowered-carbohydrate diet, a starved group and a starved-refed group. In each group the specific activity (mumol/min per g wet wt. of tissue) of hepatic glycerol 3-phosphate dehydrogenase was compared with the activities of the β-oxoacyl-(acyl-carrier protein) reductase component of fatty acid synthetase, glycerol kinase (EC 2.7.1.30) and lactate dehydrogenase (EC 1.1.1.27). 3. During starvation, the activities of glycerol 3-phosphate dehydrogenase, glycerol kinase and lactate dehydrogenase rose significantly. After re-feeding these activities returned to near normal. All three activities rose slightly on the high-fat diet. Lactate dehydrogenase activity rose slightly, whereas those of the other two enzymes fell slightly on the increased-carbohydrate-lowered-fat diet. 4. The activity of the β-oxoacyl-(acyl-carrier protein) reductase component of fatty acid synthetase, a lipid-synthesizing enzyme, contrasted strikingly with the other three enzyme activities. Its activity was slightly elevated on the increased-carbohydrate diet and significantly diminished on the high-fat diet and during starvation. 5. The changes in activity of the chicken liver isoenzyme of glycerol 3-phosphate dehydrogenase in response to dietary stresses suggest that the enzyme has an important metabolic role other than or in addition to glyceride biosynthesis.

A covalent adduct of MbtN, an acyl-ACP dehydrogenase fromMycobacterium tuberculosis, reveals an unusual acyl-binding pocket

2015 ◽  
Vol 71 (4) ◽  
pp. 862-872 ◽  
Author(s):  
Ai-Fen Chai ◽  
Esther M. M. Bulloch ◽  
Genevieve L. Evans ◽  
J. Shaun Lott ◽  
Edward N. Baker ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Acyl Carrier Protein ◽  
Acyl Chain ◽  
Binding Pocket ◽  
Carrier Protein ◽  
Strongly Correlated ◽  
Steady State Kinetics ◽  
Expected Length ◽  
Acyl Chains

Mycobacterium tuberculosis(Mtb) is the causative agent of tuberculosis. Access to iron in host macrophages depends on iron-chelating siderophores called mycobactins and is strongly correlated withMtbvirulence. Here, the crystal structure of anMtbenzyme involved in mycobactin biosynthesis, MbtN, in complex with its FAD cofactor is presented at 2.30 Å resolution. The polypeptide fold of MbtN conforms to that of the acyl-CoA dehydrogenase (ACAD) family, consistent with its predicted role of introducing a double bond into the acyl chain of mycobactin. Structural comparisons and the presence of an acyl carrier protein, MbtL, in the same gene locus suggest that MbtN acts on an acyl-(acyl carrier protein) rather than an acyl-CoA. A notable feature of the crystal structure is the tubular density projecting from N(5) of FAD. This was interpreted as a covalently bound polyethylene glycol (PEG) fragment and resides in a hydrophobic pocket where the substrate acyl group is likely to bind. The pocket could accommodate an acyl chain of 14–21 C atoms, consistent with the expected length of the mycobactin acyl chain. Supporting this, steady-state kinetics show that MbtN has ACAD activity, preferring acyl chains of at least 16 C atoms. The acyl-binding pocket adopts a different orientation (relative to the FAD) to other structurally characterized ACADs. This difference may be correlated with the apparent ability of MbtN to catalyse the formation of an unusualcisdouble bond in the mycobactin acyl chain.

scholarly journals Isolation of cDNAs from Brassica napus encoding the biotin-binding and transcarboxylase domains of acetyl-CoA carboxylase: assignment of the domain structure in a full-length Arabidopsis thaliana genomic clone

1994 ◽  
Vol 301 (2) ◽  
pp. 599-605 ◽  
Author(s):  
K M Elborough ◽  
R Swinhoe ◽  
R Winz ◽  
J T Kroon ◽  
L Farnsworth ◽  
...  
Keyword(s):  
Blot Analysis ◽  
Acyl Carrier Protein ◽  
Fatty Acid Synthetase ◽  
Genomic Clone ◽  
Full Length ◽  
Cdna Clones ◽  
Carrier Protein ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Biotin Binding

One independent and two overlapping rape cDNA clones have been isolated from a rape embryo library. We have shown that they encode a 2.3 kb and a 2.5 kb stretch of the full-length acetyl-CoA carboxylase (ACCase) cDNA, corresponding to the biotin-binding and transcarboxylase domains respectively. Using the cDNA in Northern-blot analysis we have shown that the mRNA for ACCase has a higher level of expression in rape seed than in rape leaf and has a full length of 7.5 kb. The level of expression during rape embryogenesis was compared with both oil deposition and expression of two fatty acid synthetase components enoyl-(acyl-carrier-protein) reductase and 3-oxoacyl-(acyl-carrier-protein) reductase. Levels of ACCase mRNA were shown to peak at 29 days after anthesis during embryonic development, similarly to enoyl-(acyl-carrier-protein) reductase and 3-oxoacyl-(acyl-carrier-protein) reductase mRNA. In addition, a full-length genomic clone (19 kb) of Arabidopsis ACCase has been isolated and partially sequenced. Analysis of the clone has allowed the first plant ACCase activity domains (biotin carboxylase-biotin binding-transcarboxylase) to be ordered and assigned. Southern-blot analysis using the Arabidopsis clone indicates that ACCase is a single-copy gene in Arabidopsis but is encoded by a small gene family in rape.

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