α-AMINO-n-BUTYRIC ACID IN TRANSAMINATION

1959 ◽  
Vol 37 (4) ◽  
pp. 599-604
Author(s):  
G. Y. N. Iyer ◽  
M. Sukumaran
Keyword(s):  
Skeletal Muscle ◽  
Butyric Acid ◽  
Direct Evidence ◽  
Rat Kidney ◽  
Transaminase Activity ◽  
Transamination Reaction ◽  
Kidney Liver

The transamination reaction between α-amino-n-butyric acid and α-keto-glutarate or pyruvate or oxaloacetate in the presence of homogenates of rat kidney, liver, heart, and skeletal muscle has been studied. Direct evidence is presented for transamination with α-ketoglutarate in the presence of the first three tissues and with pyruvate in the presence of kidney and liver. Appreciable amounts of alanine are formed in the course of transamination with oxaloacetate. Of the four tissues the liver appears to be quantitatively the most important by virtue of its mass and relatively high specific transaminase activity.

α-AMINO-n-BUTYRIC ACID IN TRANSAMINATION

1959 ◽  
Vol 37 (1) ◽  
pp. 599-604
Author(s):  
G. Y. N. Iyer ◽  
M. Sukumaran
Keyword(s):  
Skeletal Muscle ◽  
Butyric Acid ◽  
Direct Evidence ◽  
Rat Kidney ◽  
Transaminase Activity ◽  
Transamination Reaction ◽  
Kidney Liver

The transamination reaction between α-amino-n-butyric acid and α-keto-glutarate or pyruvate or oxaloacetate in the presence of homogenates of rat kidney, liver, heart, and skeletal muscle has been studied. Direct evidence is presented for transamination with α-ketoglutarate in the presence of the first three tissues and with pyruvate in the presence of kidney and liver. Appreciable amounts of alanine are formed in the course of transamination with oxaloacetate. Of the four tissues the liver appears to be quantitatively the most important by virtue of its mass and relatively high specific transaminase activity.

Expression of rat kidney anion exchanger 1 in type A intercalated cells in metabolic acidosis and alkalosis

1999 ◽  
Vol 277 (6) ◽  
pp. F841-F849 ◽  
Author(s):  
Saskia Huber ◽  
Esther Asan ◽  
Thomas Jöns ◽  
Christiane Kerscher ◽  
Bernd Püschel ◽  
...  
Keyword(s):  
Anion Exchanger ◽  
Direct Evidence ◽  
Rat Kidney ◽  
Enzyme Reaction ◽  
Type A ◽  
Mrna Levels ◽  
Intercalated Cells ◽  
Acid Base ◽  
Anion Exchanger 1 ◽  
Acid Base Status

By enzyme-linked in situ hybridization (ISH), direct evidence is provided that acid-secreting intercalated cells (type A IC) of both the cortical and medullary collecting ducts of the rat kidney selectively express the mRNA of the kidney splice variant of anion exchanger 1 (kAE1) and no detectable levels of the erythrocyte AE1 (eAE1) mRNA. Using single-cell quantification by microphotometry of ISH enzyme reaction, medullary type A IC were found to contain twofold higher kAE1 mRNA levels compared with cortical type A IC. These differences correspond to the higher intensity of immunostaining in medullary versus cortical type A IC. Chronic changes of acid-base status induced by addition of NH4Cl (acidosis) or NaHCO3 (alkalosis) to the drinking water resulted in up to 35% changes of kAE1 mRNA levels in both cortical and medullary type A IC. These experiments provide direct evidence at the cellular level of kAE1 expression in type A IC and show moderate capacity of type A IC to respond to changes of acid-base status by modulation of kAE1 mRNA levels.

Modulation of leucine transaminase activity by dietary means

1975 ◽  
Vol 228 (2) ◽  
pp. 432-435 ◽  
Author(s):  
SA Adibi ◽  
JA Peterson ◽  
BA Krzysik
Keyword(s):  
Skeletal Muscle ◽  
Specific Activity ◽  
Muscle Protein ◽  
Transaminase Activity ◽  
Skeletal Muscle Protein ◽  
Protein Deprivation ◽  
Experimental Conditions ◽  
Additional Increase ◽  
Remarkable Effect ◽  
Full Day

The specific activity of leucine transaminase was measured in supernatants of liver, skeletal muscle (gastrocnemius), and kidney homogenates obtained from fed, starved, and protein-deprived rats. After 12 h of starvation, there were slight reductions in leucine transaminase activity of both muscle and kidney tissues. When starvation was prolonged to 1 full day, the activity of this enzyme increased by approximately twofold in both muscle and kidney. Prolongation of fasting to 5 days resulted in an additional increase in specific activity of leucine transaminase in muscle. During the entire 5 days of starvation, leucine transaminase activity remained unaltered in liver of starved rats. Protein deprivation for 1 or 5 days resulted in significant reductions in specific activity of leucine transaminase in skeletal muscle. Protein deprivation did not produce a remarkable effect on the activity of this enzyme in kidney or liver tissue. The results of this study, together with those previously obtained, indicate that within our experimental conditions increased oxidation of leucine in skeletal muscle of starved rats is not initially related to an alteration in activity of leucine transaminase. When caloric deficiency is prolonged, the potential for transamination is also increased. These adaptive changes increase the ability of skeletal muscle to use leucine as a metabolic fuel.

Molecular analysis of intermediate filament cytoskeleton--a putative load-bearing structure

1984 ◽  
Vol 246 (4) ◽  
pp. H566-H572 ◽  
Author(s):  
M. G. Price
Keyword(s):  
Skeletal Muscle ◽  
Molecular Analysis ◽  
Intermediate Filaments ◽  
Intermediate Filament ◽  
Direct Evidence ◽  
Two Dimensional ◽  
Myocardial Cells ◽  
Intermediate Filament Proteins ◽  
Bovine Myocardium ◽  
Bearing Structure

Myocardial cells contain a cytoskeleton of intermediate filaments connecting the myofibrils. The present molecular analysis of the myocardial cytoskeleton was designed to identify the intermediate filament proteins and examine their assembly properties. The intermediate filament proteins desmin and vimentin were isolated from adult bovine myocardium by sequential extraction, urea solubilization, and chromatography on hydroxylapatite and DEAE columns. Desmin was obtained virtually pure in one peak and in a mixture of desmin and vimentin in the trailing fractions. Intermediate filaments of different morphologies polymerized in the desmin and the desmin-vimentin fractions. Isolated myocardial desmin occurs as three isozymes and isolated myocardial vimentin as two isozymes, which co-migrate on two-dimensional gels with corresponding isozymes from bovine skeletal and smooth muscle. Polypeptides of 200,000 and 220,000 daltons that fractionate with myocardial desmin and vimentin are also present in cytoskeletons of smooth and skeletal muscle. The results provide direct evidence that myocardial desmin can assemble to form intermediate filaments, suggesting that desmin is the major component of the cytoskeletal filaments in cardiomyocytes.

scholarly journals Isolation of functional mitochondria from rat kidney and skeletal muscle without manual homogenization

2011 ◽  
Vol 418 (2) ◽  
pp. 213-223 ◽  
Author(s):  
Vera S. Gross ◽  
Heather K. Greenberg ◽  
Sergei V. Baranov ◽  
Greta M. Carlson ◽  
Irina G. Stavrovskaya ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Rat Kidney

scholarly journals MEMBRANE JUNCTIONS IN THE INTERMEMBRANE SPACE OF MITOCHONDRIA FROM MAMMALIAN TISSUES

1974 ◽  
Vol 60 (3) ◽  
pp. 653-663 ◽  
Author(s):  
Akitsugu Saito ◽  
Murray Smigel ◽  
Sidney Fleischer
Keyword(s):  
Skeletal Muscle ◽  
Cross Sections ◽  
Rat Kidney ◽  
Respiratory Control ◽  
Heart Tissue ◽  
Intermembrane Space ◽  
Mitochondrial Membranes ◽  
Fresh Tissue ◽  
Isolated Mitochondria ◽  
Mammalian Tissues

There have been several reports describing paracrystalline arrays in the intermembrane space of mitochondria. On closer inspection these structures appear to be junctions of two adjoining membranes. There are two types. They can be formed between the outer and inner mitochondrial membranes (designated outer-inner membrane junctions) or between two cristal membranes (intercristal membrane junctions). In rat heart, adjoining membranes appeared associated via a central dense midline approximately 30 Å wide. In rat kidney, the junction had a ladder-like appearance with electron-dense "bridges" approximately 80 Å wide, spaced 130 Å apart, connecting the adjoining membranes. We have investigated the conditions which favor the visualization of such structures in mitochondria. Heart mitochondria isolated rapidly from fresh tissue (within 30 min of death) contain membrane junctions in approximately 10–15% of the cross sections. This would indicate that the percentage of membrane junctions in the entire mitochondrion is far greater. Mitochondria isolated from heart tissue which was stored for 1 h at 0°–4°C showed an increased number of membrane junctions, so that 80% of the mitochondrial cross sections show membrane junctions. No membrane junctions are observed in mitochondria in rapidly fixed fresh tissue or in mitochondria isolated from tissue disrupted in fixative. Thus, the visualization of junctions in the intermembrane space of mitochondria appears to be dependent upon the storage of tissue after death. Membrane junctions can also be observed in mitochondria from other stored tissues such as skeletal muscle, kidney, and interstitial cells from large and small intestine. In each case, no such junctions are observed in these tissues when they are fixed immediately after removal from the animal. It would appear that most studies in the literature in which isolated mitochondria from tissues such as heart or kidney were used were carried out on mitochondria which contained membrane junctions. The presence of such structures does not significantly affect normal mitochondrial function in terms of respiratory control and oxidative phosphorylation.

Factors affecting protein synthesis in rat kidney ribosome preparations

1970 ◽  
Vol 48 (1) ◽  
pp. 105-112 ◽  
Author(s):  
D. M. Nicholls ◽  
M. P. Ryan ◽  
S. H. Miall ◽  
I. D. Cappon
Keyword(s):  
Protein Synthesis ◽  
Rat Kidney ◽  
Insoluble Protein ◽  
Ribonuclease Inhibitor ◽  
Enzyme Preparations ◽  
Factors Affecting ◽  
Kidney Microsomes ◽  
Kidney Liver ◽  
Microsomal Pellet ◽  
Liver Ribosomes

Kidney ribosomes that were prepared from the postmitochondrial supernatant or the microsomal pellet of homogenates by deoxycholate treatment consisted mainly of monomers and dimers rather than polysomes. The addition of liver postmicrosomal supernatant to kidney homogenates or to kidney microsomes did not increase the polysome yield or the incorporation of 14C-leucine into hot acid-insoluble protein. In contrast to kidney, liver ribosomes that were prepared in the presence of liver supernatant (containing ribonuclease inhibitor) had an increased proportion of polysomes and an increased incorporation of 14C-leucine into protein compared to liver ribosomes prepared in the absence of supernatant.The incorporation of 14C-leucine into protein in kidney ribosome preparations was considerably lower than it was in liver ribosome preparations. The incorporation depended on the concentration of Mg2+, GTP, and pH 5 enzymes. Following preincubation of kidney ribosomes to eliminate endogenous mRNA, the incorporation of 14C-phenylalanine into peptide using either phenylalanine or phenylalanyl-tRNA was found to depend on the addition of poly U.Ribonuclease activity in kidney supernatant and pH 5 enzyme preparations was much greater than it was in liver preparations, and may partly account for the lower polysome yield and protein synthesis in kidney.

scholarly journals NEPHROTOXIC SERUM NEPHRITIS IN RATS

1956 ◽  
Vol 104 (4) ◽  
pp. 487-499 ◽  
Author(s):  
Howard C. Goodman ◽  
James H. Baxter
Keyword(s):  
Skeletal Muscle ◽  
Ammonium Sulfate ◽  
Protective Factor ◽  
Rat Kidney ◽  
Tryptic Digestion ◽  
Tissue Antigen ◽  
Rat Lung ◽  
High Concentration ◽  
Kidney Homogenate ◽  
Rat Tissue

A soluble protective factor, capable of absorbing nephrotoxic antibodies from anti-rat kidney serum, can be obtained in high concentration by tryptic digestion of rat kidney homogenate. The factor is no longer antigenic or at most only slightly so. It is stable at 60°, destroyed by boiling, is non-dialyzable, can be precipitated by ammonium sulfate, but resists destruction by proteolytic and other enzymes. In accord with previous studies on the organ localization of the rat tissue antigen responsible for the production of nephrotoxic antibodies, the soluble protective factor, or antigen derivative, can be obtained by tryptic digestion of rat lung, skeletal muscle, heart, and liver.

scholarly journals Leucine degradation in cell-free extracts of skeletal muscle

1979 ◽  
Vol 178 (2) ◽  
pp. 475-489 ◽  
Author(s):  
R Odessey ◽  
A L Goldberg
Keyword(s):  
Skeletal Muscle ◽  
Competitive Inhibition ◽  
Primary Source ◽  
Mitochondrial Fraction ◽  
The Body ◽  
Oxidative Decarboxylation ◽  
Transaminase Activity ◽  
Leucine Oxidation ◽  
Activity Measurements

Since skeletal muscle is the major site in the body for oxidation of leucine, isoleucine and valine, the pathway and control of leucine oxidation were investigated in cell-free preparations of rat muscle. Leucine was found to be transaminated to 4-methyl-2-oxopentanoate, which was then oxidatively decarboxylated. On differential centrifugation 70–80% of the transaminase activity was recovered in the soluble fraction of the cell, and the remaining amount in the mitochondrial fraction. The transaminase, from both fractions had similar pH optima and both were markedly inhibited by Ca2+. Thus changes in cellular Ca2+ concentration may regulate transaminase activity. Both transaminases had a much higher affinity for 2-oxoglutarate than for pyruvate. Therefore the utilization of amino groups from leucine for the biosynthesis of alanine in muscle [Odessey, Khairallah & Goldberg (1974) J. Biol. Chem. 249, 7623–7629] in vivo involves transamination with 2-oxoglutarate to produce glutamate, which is then transaminated with pyruvate to produce alanine. The dehydrogenase activity assayed by the decarboxylation of methyl-2-oxo[1-14C]pentanoate was localized exclusively in the fraction containing mitochondria and required NAD+, CoA and thiamin pyrophosphate for optimal activity. Measurements of competitive inhibition suggested that the oxo acids of leucine, isoleucine and valine are all decarboxylated by the same enzyme. The enzyme activity was decreased by 90% upon freezing or sonication and was stimulated severalfold by Mg2+, K+ and phosphate ions. In addition, it was markedly inhibited by ATP, but not by non-metabolizable analogues. This observation suggests that splitting of ATP is required for inhibition. The oxidative decarboxylation of 4-methyl-2-oxopentanoate by the dehydrogenase appears to be the rate-limiting step for leucine oxidation in muscle homogenates and also in intact tissues. In fact, rat muscles incubated with [1-14C]leucine release 1-14C-labelled oxo acid into the medium at rates comparable with the rate of decarboxylation. Intact muscles also released the oxo acids of [1-14C]valine or [1-14C]isoleucine, but not of other amino acids. These findings suggest that muscle is the primary source of the branched-chain oxo acids found in the blood.

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