scholarly journals Enzymic studies on the biosynthesis of amino acids from lactate by Peptostreptococcus elsdenii

1968 ◽  
Vol 108 (1) ◽  
pp. 107-119 ◽  
Author(s):  
H. J. Somerville
Keyword(s):  
Amino Acids ◽  
Strong Evidence ◽  
Malic Enzyme ◽  
Inorganic Phosphate ◽  
Radioactive Tracer ◽  
Tricarboxylic Acid ◽  
Glutamate Oxaloacetate Transaminase ◽  
Tracer Studies ◽  
Strict Anaerobe ◽  
Acid Pathway

Cell-free extracts of Peptostreptococcus elsdenii, a strict anaerobe from the rumen, were examined for enzymes catalysing the steps in the biosynthesis from lactate of alanine, serine, aspartate and glutamate. Extracts contain the enzymes necessary for the formation of alanine from lactate via pyruvate. The presence of enzymes catalysing the interconversion of phosphoglycerate and phosphohydroxypyruvate, the transamination of the latter to phosphoserine and the cleavage of phosphoserine to serine and inorganic phosphate was demonstrated, suggesting that serine is formed via these intermediates. ‘Malic’ enzyme, malate dehydrogenase and glutamate–oxaloacetate transaminase are present in extracts and could account for aspartate formation. The extracts catalyse all of the steps of the tricarboxylic acid pathway leading from oxaloacetate plus acetate to glutamate. Together with substantive data from previous radioactive tracer studies the results provide strong evidence that these four amino acids are synthesized in this strict anaerobe by pathways closely similar to those operating in aerobic and facultatively aerobic organisms.

scholarly journals Tracer studies on the biosynthesis of amino acids from lactate by Peptostreptococcus elsdenii

1967 ◽  
Vol 105 (1) ◽  
pp. 299-310 ◽  
Author(s):  
H. J. Somerville ◽  
J. L. Peel
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Carbon Chain ◽  
Tricarboxylic Acid ◽  
Diaminopimelic Acid ◽  
Reaction Sequence ◽  
Tracer Studies ◽  
Cell Fractions

Peptostreptococcus elsdenii, a strict anaerobe from the rumen, was grown on a medium containing yeast extract and [1−14C]- or [2−14C]-lactate. Radioisotope from lactate was found in all cell fractions, but mainly in the protein. The label in the protein fraction was largely confined to a few amino acids: alanine, serine, aspartic acid, glutamic acid and diaminopimelic acid. The alanine, serine, aspartic acid and glutamic acid were separated, purified and degraded to establish the distribution of 14C from lactate within the amino acid molecules. The labelling patterns in alanine and serine suggested their formation from lactate without cleavage of the carbon chain. The pattern in aspartic acid suggested formation by condensation of a C3 unit derived directly from lactate with a C1 unit, probably carbon dioxide. The distribution in glutamic acid was consistent with two possible pathways of formation: (a) by the reactions of the tricarboxylic acid cycle leading from oxaloacetate to 2-oxoglutarate, followed by transamination; (b) by a pathway involving the reaction sequence 2 acetyl-CoA→crotonyl-CoA→glutaconate→glutamate.

The tricarboxylic acid pathway in Desulfovibrio

1977 ◽  
Vol 23 (7) ◽  
pp. 916-921 ◽  
Author(s):  
A. J. Lewis ◽  
J. D. A. Miller
Keyword(s):  
Yeast Extract ◽  
Malic Enzyme ◽  
Pyruvate Carboxylase ◽  
Tricarboxylic Acid Cycle ◽  
Glyoxylate Cycle ◽  
Dicarboxylic Acids ◽  
Tricarboxylic Acid ◽  
Desulfovibrio Vulgaris ◽  
Acid Cycle ◽  
Acid Pathway

Strains of two species of Desulfovibrio were examined for enzymes of the tricarboxylic acid cycle and related pathways. Pyruvate carboxylase (EC 6.4.1.1) is present, and α-ketoglutarate is formed via the tricarboxylic acids. Glutamate, but not succinyl-CoA, arises from α-ketoglutarate. A pathway exists from pyruvate by malic enzyme (EC 1.1.1.39) activity to malate, then fumarate and succinate, again with no evidence of succinyl-CoA formation. The enzymes concerned with metabolism of these dicarboxylic acids show greater activity in the strains that can grow by fumarate dismutation. Glutamate (or glutamine), α-ketoglutarate, and yeast extract repress the enzymes that metabolize the tricarboxylic acids. There appears to be no glyoxylate cycle in Desulfovibrio vulgaris or D. desulfuricans.

UTILIZATION OF CARBOHYDRATES AND AMINO ACIDS BY MICROCOCCUS RADIODURANS

1960 ◽  
Vol 6 (3) ◽  
pp. 289-298 ◽  
Author(s):  
Harkison D. Raj ◽  
Frances L. Duryee ◽  
Anne M. Deeney ◽  
Chih H. Wang ◽  
Arthur W. Anderson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Tricarboxylic Acid Cycle ◽  
Radioactive Tracer ◽  
Defined Medium ◽  
Tricarboxylic Acid ◽  
Chemically Defined Medium ◽  
Acid Cycle ◽  
Tracer Techniques ◽  
Simple Carbohydrates

The nutrition and metabolism of a recently isolated Micrococcus species resistant to closes of gamma radiation as high as 6 × 106 r.e.p. were studied by manometric and radioactive tracer techniques. Methionine, the only amino acid shown to be essential in a chemically defined medium, appears to be rapidly incorporated into the cells. DL-Glutamic acid is readily metabolized, the D isomer apparently after an initial lag. Among the simple carbohydrates, fructose, glucose, and glycerol are readily utilized. The operation of the tricarboxylic acid cycle is suggested by the oxidation of certain TCA intermediates. The prompt conversion of C-1 of gluconate to CO2, in the presence of glucose, may indicate that a C1–C5 cleavage pathway is operative for catabolism of glucose in this organism.

Biosynthesis of amino acids byOxalobacter formigenes: analysis using13C-NMR

1996 ◽  
Vol 42 (12) ◽  
pp. 1219-1224 ◽  
Author(s):  
Nancy A. Cornick ◽  
Bin Yan ◽  
Shelton Bank ◽  
Milton J. Allison
Keyword(s):  
Amino Acids ◽  
Carbon Assimilation ◽  
Aromatic Amino Acids ◽  
Tricarboxylic Acid ◽  
Acetate Incorporation ◽  
Oxalobacter Formigenes ◽  
Subsequent Formation ◽  
Acid Pathway ◽  
Growth Experiments ◽  
Labeling Pattern

The gram-negative anaerobe Oxalobacter formigenes, grows on oxalate as the principal carbon and energy source, but a small amount of acetate is also required for growth. Experiments were conducted to determine the distribution and the position of label in cellular amino acids from cells grown on [13C]oxalate, [13C]acetate (1-13C, 2-13C, and U-13C), and13CCO3. The labeling pattern (determined with NMR spectroscopy) of amino acids was consistent with their formation through common biosynthetic pathways. The majority of the carbons in the amino acids that are usually derived from pyruvate, oxaloacetate, α-ketoglutarate, 3-phosphoglycerate, and carbon in the aromatic amino acids were labeled by oxalate. Carbon from13CO3was assimilated primarily into amino acids expected to be derived from oxaloacetate and α-ketoglutarate. Approximately 60% of the acetate that was assimilated into amino acids was incorporated as a C2unit into proline, arginine, glutamate, and leucine. The pattern of labeling from acetate in glutamate, arginine, and proline was consistent with acetate incorporation via citrate (si)-synthase and subsequent formation of α-ketoglutarate via the first third of the tricarboxylic acid pathway. Acetate was also assimilated into amino acids derived from pyruvate and oxaloacetate, but results indicated that this incorporation was as single carbon atoms. Based on these findings, cell-free extracts were assayed for several key biosynthetic enzymes. Enzymatic activities found included glutamate dehydrogenase, phosphoenolpyruvate carboxylase, and pyruvate carboxylase. These findings are consistent with proposed biosynthetic mechanisms.Key words: oxalate, carbon flow, carbon assimilation.

Guidelines for Radioactive Tracer Studies of the Heart and Circulation

Radiology ◽  
1975 ◽  
Vol 116 (1) ◽  
pp. 229-230
Author(s):  
S. James Adelstein
Keyword(s):  
Radioactive Tracer ◽  
Tracer Studies

scholarly journals Metabolic Changes of Amino Acids and Flavonoids in Tea Plants in Response to Inorganic Phosphate Limitation

2018 ◽  
Vol 19 (11) ◽  
pp. 3683 ◽  
Author(s):  
Santosh KC ◽  
Meiya Liu ◽  
Qunfeng Zhang ◽  
Kai Fan ◽  
Yuanzhi Shi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Inorganic Phosphate ◽  
Tea Plant ◽  
Phosphate Limitation ◽  
P Limitation ◽  
Metabolic Genes ◽  
Expression Of Genes ◽  
Tea Plants ◽  
Change Response ◽  
Tof Ms

The qualities of tea (Camellia sinensis) are not clearly understood in terms of integrated leading molecular regulatory network mechanisms behind inorganic phosphate (Pi) limitation. Thus, the present work aims to elucidate transcription factor-dependent responses of quality-related metabolites and the expression of genes to phosphate (P) starvation. The tea plant organs were subjected to metabolomics analysis by GC×GC-TOF/MS and UPLC-Q-TOF/MS along with transcription factors and 13 metabolic genes by qRT-PCR. We found P starvation upregulated SPX2 and the change response of Pi is highly dependent on young shoots. This led to increased change in abundance of carbohydrates (fructose and glucose), amino acids in leaves (threonine and methionine), and root (phenylalanine, alanine, tryptophan, and tyrosine). Flavonoids and their glycosides accumulated in leaves and root exposed to P limitation was consistent with the upregulated expression of anthocyanidin reductase (EC 1.3.1.77), leucoanthocyanidin dioxygenase (EC 1.4.11.19) and glycosyltransferases (UGT78D1, UGT78D2 and UGT57L12). Despite the similar kinetics and high correlation response of Pi and SPX2 in young shoots, predominating theanine and other amino acids (serine, threonine, glutamate, valine, methionine, phenylalanine) and catechin (EGC, EGCG and CG) content displayed opposite changes in response to Pi limitation between Fengqing and Longjing-43 tea cultivars.

Nonenzymatic Catalysis by Metal Ions and Phosphoric Acid Esters of Hydroxamic Acid Formation

1980 ◽  
Vol 35 (6) ◽  
pp. 727-730
Author(s):  
Oemer Saygin ◽  
Peter Decker
Keyword(s):  
Amino Acids ◽  
Phosphoric Acid ◽  
Metal Ions ◽  
Inorganic Phosphate ◽  
Hydroxamic Acid ◽  
Hydroxamic Acids ◽  
Bivalent Ions ◽  
No Release ◽  
Catalytic Effects ◽  
Acid Esters

Abstract Nonenzymatic catalysis by bivalent ions of Be, Mg, Ca, Zn, Mn, Ni and Co and bioorganic phosphates of the formation of hydroxamic acids from acetate or amino acids has been studied systematically. Increased yields of hydroxamate were observed at particular combinations of reactants. The most prominent increase (ca. 15-fold) was found with acetate and Ni++, and with a combination of ATP and Be++. Among others especially ribose-5-phosphate and glucose-5-phosphate enhanced yields in the presence of most metal ions. Since no release of inorganic phosphate was observed, this effect cannot be interpreted as an evidence for intermediate transhosphorylation reactions; it may also result from simple catalytic effects of metal sugar complexes.

scholarly journals Neuronal-glial metabolism under depolarizing conditions. A 13C-n.m.r. study

1992 ◽  
Vol 282 (1) ◽  
pp. 225-230 ◽  
Author(s):  
R S Badar-Goffer ◽  
O Ben-Yoseph ◽  
H S Bachelard ◽  
P G Morris
Keyword(s):  
Amino Acids ◽  
Glial Cells ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Maximum Percentage ◽  
Theoretical Maximum ◽  
Metabolic Pool ◽  
Time Courses ◽  
The Individual

Time courses of incorporation of 13C from 13C-labelled glucose and/or acetate into the individual carbon atoms of amino acids, citrate and lactate in depolarized cerebral tissues were monitored by using 13C-n.m.r. spectroscopy. There was no change in the maximum percentage of 13C enrichments of the amino acids on depolarization, but the maxima were reached more rapidly, indicating that rates of metabolism in both glycolysis and the tricarboxylic acid cycle were accelerated. Although labelling of lactate and of citrate approached the theoretical maximum of 50%, labelling of the amino acids was always below 20%, suggesting that there is a metabolic pool or compartment that is inaccessible to exogenous substrates. Under resting conditions labelling of citrate and of glutamine from [1-13C]glucose was not detected, whereas both were labelled from [2-13C]acetate, which is considered to reflect glial metabolism. In contrast, considerable labelling of these two metabolites from [1-13C]glucose was observed in depolarized tissues, suggesting that the increased metabolism may be due to increased consumption of glucose by glial cells. The labelling patterns on depolarization from [1-13C]glucose alone and from both precursors [( 1-13C]glucose plus [2-13C]acetate) were similar, which also indicates that the changes are due to increased consumption of glucose rather than acetate.

Renal responses of trout to chronic respiratory and metabolic acidoses and metabolic alkalosis

1999 ◽  
Vol 277 (2) ◽  
pp. R482-R492 ◽  
Author(s):  
Chris M. Wood ◽  
C. Louise Milligan ◽  
Patrick J. Walsh
Keyword(s):  
Amino Acids ◽  
Alanine Aminotransferase ◽  
Inorganic Phosphate ◽  
Metabolic Alkalosis ◽  
Titratable Acidity ◽  
Low Ph ◽  
Similar Increase ◽  
Urine Ph ◽  
Inorganic Phosphate Excretion ◽  
Renal Responses

Exposure to hyperoxia (500–600 torr) or low pH (4.5) for 72 h or NaHCO3 infusion for 48 h were used to create chronic respiratory (RA) or metabolic acidosis (MA) or metabolic alkalosis in freshwater rainbow trout. During alkalosis, urine pH increased, and [titratable acidity (TA) −[Formula: see text]] and net H+ excretion became negative (net base excretion) with unchanged [Formula: see text] efflux. During RA, urine pH did not change, but net H+ excretion increased as a result of a modest rise in [Formula: see text] and substantial elevation in [TA −[Formula: see text]] efflux accompanied by a large increase in inorganic phosphate excretion. However, during MA, urine pH fell, and net H+excretion was 3.3-fold greater than during RA, reflecting a similar increase in [TA −[Formula: see text]] and a smaller elevation in phosphate but a sevenfold greater increase in[Formula: see text] efflux. In urine samples of the same pH, [TA − [Formula: see text]] was greater during RA (reflecting phosphate secretion), and[Formula: see text] was greater during MA (reflecting renal ammoniagenesis). Renal activities of potential ammoniagenic enzymes (phosphate-dependent glutaminase, glutamate dehydrogenase, α-ketoglutarate dehydrogenase, alanine aminotransferase, phospho enolpyruvate carboxykinase) and plasma levels of cortisol, phosphate, ammonia, and most amino acids (including glutamine and alanine) increased during MA but not during RA, when only alanine aminotransferase increased. The differential responses to RA vs. MA parallel those in mammals; in fish they may be keyed to activation of phosphate secretion by RA and cortisol mobilization by MA.

BIOSYNTHESIS OF THE COUMARINS. TRACER STUDIES ON COUMARIN FORMATION IN HIEROCHLOË ODORATA AND MELILOTUS OFFICINALIS

1960 ◽  
Vol 38 (2) ◽  
pp. 143-156 ◽  
Author(s):  
Stewart A. Brown ◽  
G. H. N. Towers ◽  
D. Wright
Keyword(s):  
Cinnamic Acid ◽  
Shikimic Acid ◽  
Perennial Grass ◽  
Coumaric Acid ◽  
Sweet Clover ◽  
Tracer Studies ◽  
Melilotus Officinalis ◽  
Specific Activities ◽  
Acid Pathway ◽  
Hierochloe Odorata

Coumarin formation has been studied with C14in the perennial grass, Hierochloë odorata, and in yellow sweet clover, Melilotus officinalis. In general the latter species yielded inconsistent data. In Hierochloë, o-coumaric, cinnamic, and shikimic acids and L-phenylalanine were the best of 10 compounds tested as coumarin precursors, the first two at least being incorporated with little randomization of C14. Acetate was more poorly utilized. It was concluded that the aromatic ring of coumarin arises via the shikimic acid pathway in preference to acetate condensation. When the time of metabolism was varied, o-coumaryl glucoside and free o-coumaric acid rapidly acquired high specific activities from cinnamic acid-C14, but coumarin and melilotic acid became active much more slowly. A lag in the acquisition of C14by coumarin for the first 6 to 8 hours was followed by a rectilinear increase until at least 24 hours. Much the greatest accumulation of C14was found in o-coumaryl glucoside during this entire period. Furthermore, this compound when fed to Hierochloë is comparable to cinnamic acid as a coumarin precursor. These findings suggest a possible function for o-coumaryl glucoside or a derivative in coumarin biosynthesis.

Sign in / Sign up

Export Citation Format

Share Document