Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.1.1.1 (alcohol dehydrogenase)
 9,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

N alpha-Acetyltransferase, which catalyzes the transfer of an acetyl group from acetyl coenzyme A to the alpha-NH2 group of proteins and peptides, was isolated from Saccharomyces cerevisiae and demonstrated by protein sequence analysis to be NH2-terminally blocked. The enzyme was purified 4,600-fold to apparent homogeneity by successive purification steps using DEAE-Sepharose, hydroxylapatite, DE52 cellulose, and Affi-Gel blue. The Mr of the native enzyme was estimated to be 180,000 +/- 10,000 by gel filtration chromatography, and the Mr of each subunit was estimated to be 95,000 +/- 2,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme has a pH optimum near 9.0, and its pI is 4.3 as determined by chromatofocusing on Mono-P. The enzyme catalyzed the transfer of an acetyl group to various synthetic peptides, including human adrenocorticotropic hormone (ACTH) (1-24) and its [Phe2] analogue, yeast alcohol dehydrogenase I (1-24), yeast alcohol dehydrogenase II (1-24), and human superoxide dismutase (1-24). These peptides contain either Ser or Ala as NH2-terminal residues which together with Met are the most commonly acetylated NH2-terminal residues (Persson, B., Flinta, C., von Heijne, G., and Jornvall, H. (1985) Eur. J. Biochem. 152, 523-527). Yeast enolase, containing a free NH2-terminal Ala residue, is known not to be N alpha-acetylated in vivo (Chin, C. C. Q., Brewer, J. M., and Wold, F. (1981) J. Biol. Chem. 256, 1377-1384), and enolase (1-24), a synthetic peptide mimicking the protein's NH2 terminus, was not acetylated in vitro by yeast acetyltransferase. The enzyme did not catalyze the N alpha-acetylation of other synthetic peptides including ACTH(11-24), ACTH(7-38), ACTH(18-39), human beta-endorphin, yeast superoxide dismutase (1-24). Each of these peptides has an NH2-terminal residue which is rarely acetylated in proteins (Lys, Phe, Arg, Tyr, Val, respectively). Among a series of divalent cations, Cu2+ and Zn2+ were demonstrated to be the most potent inhibitors. The enzyme was inactivated by chemical modification with diethyl pyrocarbonate and N-bromosuccinimide.
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PMID:Purification and characterization of an N alpha-acetyltransferase from Saccharomyces cerevisiae. 284 92

A tilt-table test was performed on 12 untrained subjects to evaluate the humoral adaptation to postural change. The observed peripheral reaction with a reversible short-term rise of norepinephrine (NE) and plasma renin activity (PRA) allowed us to divide the syndrome of the orthostatic dysregulation into a hyponoradrenergic and hypernoradrenergic type. This classification can be helpful for the clinical evaluation and therapy of orthostatic lability. The central excessive stimulation of the antidiuretic (ADH) and adrenocorticotropic hormone (ACTH) follow-ing orthostatic symptoms such as weakness or dizziness was not completely reversible within the observation period of 30 min. The ADH and ACTH increase was not different between the hypo- and the hypernoradrenergic type of dysregulation but was the most sensitive indicator of orthostatic lability: 41% of all subjects showed a hypernoradrenergic orthostatic dysregulation with pronounced NE response and alpha 2-adrenoceptor down-regulation. By use of antiembolism stockings (AES) or dihydroergotamine (DHE) this rate decreased to 16%. This was associated with a significantly reduced NE and PRA response and a diminished alpha 2-adrenoceptor number.
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PMID:Humoral regulation of the orthostatic reaction. 284 55

Protein carboxyl methyltransferase and protein methylesterase activity was assayed in various cell fractions prepared from rat livers. Significant amounts of protein carboxyl methyltransferase were detected in the cytosol and nucleoplasm. The cellular concentration of this enzyme paralleled development, activity being highest in the liver from young animals. If methylation was inhibited at any point during the reaction with S-adenosylhomocysteine, protein methylesterase activity was evident by a rapid decrease in carboxyl-methylated proteins. Protein methylesterase activity could be assessed by measuring the amount of [3H]methanol present in reaction filtrates. After a 10-min lag, the rate of demethylation was equivalent to the rate of methylation. The turnover of methyl groups was primarily enzymatic, since little or no methanol was generated when adrenocorticotropic hormone was incubated with purified protein carboxyl methyltransferase. Assessment of protein methylesterase activity as a function of the amount of methanol in the reaction filtrates represents minimal values, since the resultant [3H]methanol was metabolized rapidly via an alcohol dehydrogenase and/or oxidase. The rapid turnover of the protein methyl esters makes it difficult to assess the endogenous methyl acceptor proteins. Protein methyl esters were not detectable in any significant amounts in hepatic cell fractions in vivo; however, the nuclei contained measurable amounts of carboxyl-methylated proteins in vitro. These proteins are firmly bound to DNA but are not an integral part of the nucleosome. Analysis of the proteins, after fractionation on hydroxylapatite and sodium dodecyl sulfate-acrylamide gel electrophoresis, revealed that several non-histone chromosomal proteins were carboxyl methylated. The approximate molecular weights of these proteins were 172K, 106K, 98K, 81K, 66K, 62K, 52K, and 38K.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Protein carboxyl methylation-demethylation system in developing rat livers. 300 Apr 39

Objective: Hypothyroidism is not commonly considered a cause of hyperkalemia. We previously reported that hyperkalemia was observed mainly in elderly patients treated with renin-angiotensin-aldosterone system (RAS) inhibitors when levothyroxine treatment was withdrawn for the thyroidectomized patients with thyroid carcinoma to undergo radioactive iodine treatment. Here, we investigated whether acute hypothyroidism causes hyperkalemia in patients who were not treated with RAS inhibitors. We also investigated factors influencing potassium metabolism in hypothyroid patients. Methods: We conducted a single-center, prospective cohort study of 46 Japanese patients with thyroid carcinoma undergoing levothyroxine withdrawal prior to radioiodine therapy. All patients were normokalemic before levothyroxine withdrawal. Blood samples were analyzed 3 times: before, and at 3 and 4 weeks after levothyroxine withdrawal. We investigated factors that may be associated with the elevation of serum potassium levels from a euthyroid state to a hypothyroid state. Results: None of the patients developed symptomatic hyperkalemia. The mean serum potassium level was significantly higher at 4 weeks after levothyroxine withdrawal compared to baseline. The serum sodium levels, the estimated glomerular filtration rate (eGFR), and the plasma renin activity (PRA) decreased significantly as hypothyroidism advanced. In contrast, the plasma levels of adrenocorticotropic hormone, cortisol, aldosterone, and antidiuretic hormone were not changed, while serum thyroid hormone decreased. At 4 weeks after their levothyroxine withdrawal, the patients' serum potassium values were significantly correlated with the eGFR and the PRA. Conclusion: Acute hypothyroidism can cause a significant increase in the serum potassium level, which may be associated with a decreased eGFR and decreased circulating RAS. Abbreviations: ACTH = adrenocorticotropic hormone; ADH = antidiuretic hormone; ATPase = adenosine triphosphatase; eGFR = estimated glomerular filtration rate; HbA1c = glycated hemoglobin; K+ = potassium; Na+ = sodium; PRA = plasma renin activity; RAS = renin-angiotensin-aldosterone system; T4 = thyroxine; TSH = thyroid-stimulating hormone.
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PMID:RENAL FUNCTION AND PLASMA RENIN ACTIVITY AS POTENTIAL FACTORS CAUSING HYPERKALEMIA IN PATIENTS WITH THYROID CARCINOMA UNDERGOING THYROID HORMONE WITHDRAWAL FOR RADIOACTIVE IODINE THERAPY. 3165