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Results for “AMINO ACID METABOLISM”

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At least 721 records · Page 40Linked to original sources
PubMed1978

A defect in branched-chain amino acid metabolism in a patient with congenital lactic acidosis due to dihydrolipoyl dehydrogenase deficiency.

In a case of dihydrolipoyl dehydrogenase deficiency, there was not only an elevation of lactate and alpha-ketoglutarate but also of branched chain amino acids. The levels of branched-chain amino acids varied from the normal range to three times the upper limit of normal during the patient's lifetime, and alloisoleucine was detectable at all times. Examination of postmortem tissues revealed that the activity of branched-chain keto acid dehydrogenases was between zero and 10% of that in control tissues. It is suggested that the multiple defects seen in oxidative decarboxylation in this patient is the consequence of a single genetic deletion of an enzyme common to pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and branched chain keto acid dehydrogenases.

Acidosis↗
PubMed1985

Nutrition support of inborn errors of amino acid metabolism.

Programs for nutrition support of patients with phenylketonuria, maternal phenylketonuria, branched chain ketoaciduria and vitamin B-6 non-responsive homocystinuria were written in BASIC. These programs plan diets to fill diet prescriptions using natural foods, available amino acid-free or restricted elemental products, milk or infant proprietary formulae and protein-free fat and carbohydrate sources. Emphasis is placed on satisfying the amino acid and protein prescriptions simultaneously. The final semisynthetic formula is evaluated for vitamins, minerals, renal solute load and renal net acid excretion. Fluid requirement is estimated. The paper describes how the conventional protocols are enhanced by computerization and details the requisite calculations.

Amino Acid Metabolism, Inborn Errors↗
PubMed1990

Effects of heat shock on amino Acid metabolism of cowpea cells.

When cowpea (Vigna unguiculata) cells maintained at 26 degrees C are transferred to 42 degrees C, rapid accumulation of gamma-aminobutyrate (>10-fold) is induced. Several other amino acids (including beta-alanine, alanine, and proline) are also accumulated, but less extensively than gamma-aminobutyrate. Total free amino acid levels are increased approximately 1.5-fold after 24 hours at 42 degrees C. Heat shock also leads to release of amino acids into the medium, indicating heat shock damage to the integrity of the plasmalemma. Some of the changes in metabolic rates associated with heat shock were estimated by monitoring the (15)N labeling kinetics of free intracellular, extracellular and protein-bound amino acids of cultures supplied with (15)NH(4) (+), and analyzing the labeling data by computer simulation. Preliminary computer simulation models of nitrogen flux suggest that heat shock induces an increase in the gamma-aminobutyrate synthesis rate from 12.5 nanomoles per hour per gram fresh weight in control cells maintained at 26 degrees C, to as high as 800 nanomoles per hour per gram fresh weight within the first 2 hours of heat shock. This 64-fold increase in the gamma-aminobutyrate synthesis rate greatly exceeds the expected (Q(10)) change of metabolic rate of 2.5- to 3-fold due to a 16 degrees C increase in temperature. We suggest that this metabolic response may in part involve an activation of glutamate decarboxylase in vivo, perhaps mediated by a transient cytoplasmic acidification. Proline appears to be synthesized from glutamate and not from ornithine in cowpea cells. Proline became severalfold more heavily labeled than ornithine, citrulline and arginine in both control and heat-shocked cultures. Proline synthesis rate was increased 2.7-fold by heat shock. Alanine, beta-alanine, valine, leucine, and isoleucine synthesis rates were increased 1.6-, 3.5-, 2.0-, 5.0-, and 6.0-fold, respectively, by heat shock. In contrast, the phenylalanine synthesis rate was decreased by 50% in response to heat shock. The differential effects of heat stress on metabolic rates lead to flux and pool size redistributions throughout the entire network of amino acid metabolism.

Journal Article↗