Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method is described for the purification of the enzyme aspartate aminotransferase from the thermophile Thermus aquaticus. The enzyme has been characterized with respect to its molecular weight on SDS PAGE and by amino acid analysis. Attempts to obtain N-terminal sequence data was unsuccessful, presumably due to a blocked N-terminus. The purified enzyme has been shown to be highly thermostable, having a half life of inactivation of about 6 hours at 100 degrees C, and to have a temperature optimum greater than 95 degrees C.
Biochem Mol Biol Int 1993 Apr
PMID:Purification of aspartate aminotransferase from Thermus aquaticus. 850 40

Propolis (bee glue) is one of the major hive products of bees and is rich in flavonoids, which are known for antioxidant activities. Doxorubicin-induced myocardiopathy is the consequence of oxidative stress through the mediation of free radicals. The effect of intraperitoneal administration of propolis (50 and 100 mg/kg) was studied on cardiomyopathy produced by doxorubicin (10 mg/kg, i.v.) in rats. Serum creatine phosphokinase (CK), aspartate aminotransferase (AST), blood and tissue glutathione (GSH), and thiobarbituric acid reactive substances (TBARS) in heart were estimated to assess the status of heart muscle. An elevation of the levels of CK, AST, GSH, and TBARS was observed following doxorubicin treatment. Parallel experiments with a pretreatment of propolis significantly reduced the levels of these parameters . Biochemical observations were supplemented by histopathological examination of heart sections. The protective effect of propolis was compared with that of rutin, a known cardioprotective flavonoid. The study demonstrates the cardioprotective effect of propolis in doxorubicin-induced experimental cardiotoxicity.
Exp Mol Pathol 1995 Jun
PMID:Propolis protects against doxorubicin-induced myocardiopathy in rats. 861 23

The levels of activity of some enzymes involved in oxidative metabolism have been determined in left ventricular tissue from spontaneously hypertensive rats compared with those in normotensive controls. Levels of pyruvate kinase were increased about 1.3 fold indicative of elevated glycolytic activity. Similarly, enhanced levels of lactate dehydrogenase were found, consistent with a requirement for increased oxidation of cytosolically-generated NADH. In addition a more active malate-aspartate shuttle, which in heart provides the major route for transfer of reducing equivalents to the mitochondria, was suggested by elevated levels of the cytosolic isoenzyme of aspartate aminotransferase; malate dehydrogenase did not increase but the activity of this enzyme is very high and unlikely to be rate-limiting in the shuttle. The levels of expression of mRNAs for three of these enzymes (pyruvate kinase, aspartate aminotransferase and malate dehydrogenase) were also determined and correlated well with the extent of change, if any, in the changes in enzymatic activity. Thus it seems that one response to development of hypertension in rats is an increase in expression of the genes for certain key enzymes involved in oxidative metabolism.
Biochem Mol Biol Int 1995 Nov
PMID:Changes in enzyme levels in hypertensive heart tissue. 862 6

The FruR regulator of Escherichia coli controls the initiation of transcription of several operons encoding a variety of proteins involved in carbon and energy metabolism. The sequence determinants of the FruR-binding site were analysed by using 6x His-tagged FruR and a series of double-stranded randomized oligonucleotides. FruR consensus binding sites were selected and characterized by several consecutive rounds of the polymerase chain reaction-assisted binding-site selection method (BSS) using nitrocellulose-immobilized DNA-binding protein. FruR was demonstrated to require, for binding, an 8 bp left half-site motif and a 3 bp conserved right half-site with the following sequence: 5'-GNNGAATC/GNT-3'. In this sequence, the left half-site AATC/ consensus tetranucleotide is a typical motif of the DNA-binding site of the regulators of the GalR-Lacl family. On the other hand, the high degree of degeneracy found in the right half-site of this palindrome-like structure indicated that FruR, which is a tetramer in solution, interacts asymmetrically with the two half-sites of its operator. However, potentially FruR-target sites showing a high degree of symmetry were detected in 13 genes/operons. Among these, we have focused our interest on the pfkA gene, encoding phosphofructo-kinase-1, which is negatively regulated by FruR.
Mol Microbiol 1996 Jul
PMID:Definition of a consensus DNA-binding site for the Escherichia coli pleiotropic regulatory protein, FruR. 885 81

The cytosolic heat shock cognate 70-kDa protein (hsc70) is required for efficient import of ornithine transcarbamylase precursor (pOTC) into rat liver mitochondria (K. Terada, K. Ohtsuka, N. Imamoto, Y. Yoneda, and M. Mori, Mol. Cell. Biol. 15:3708-3713, 1995). The requirement of hsc70 for mitochondrial import of various precursor proteins and truncated pOTCs was studied by using an in vitro translation import system in which hsc70 was completely depleted. hsc70-dependent import of pOTC was about 60% of the total import, while import of the aspartate aminotransferase precursor, the serine:pyruvate aminotransferase precursor, and 3-oxoacyl coenzyme A thiolase was about 50, 30, and 0%, respectively. The subunit sizes of these four precursor proteins were 40 to 47 kDa. When pOTC was serially truncated from the COOH terminal, the hsc70 requirement decreased gradually and was not evident for the shortest truncated pOTCs of 90 and 72 residues. These truncated pOTCs were imported and proteolytically processed rapidly in 0.5 to 2 min at 25 degrees C, and the processed mature portions and the presequence portion were rapidly degraded. Sucrose gradient centrifugation analysis followed by import assay showed that pOTC synthesized in rabbit reticulocyte lysate forms an import-competent complex of about 11S in an hsc70-dependent manner. S values of import-competent forms of aspartate aminotransferase precursor, serine:pyruvate aminotransferase precursor, and 3-oxoacyl coenzyme A thiolase were 9S, 9S, and 4S, respectively. Thus, the S value decreased as the hsc70 dependency decreased. Precursor proteins were coimmunoprecipitated from the reticulocyte lysate containing the newly synthesized precursor proteins with an hsc70 antibody. The amount of coimmunoprecipitated proteins was much larger in the absence of ATP than in its presence. Among the four precursor proteins, the amount of coimmunoprecipitated protein decreased as the hsc70 dependency decreased.
Mol Cell Biol 1996 Nov
PMID:The requirement of heat shock cognate 70 protein for mitochondrial import varies among precursor proteins and depends on precursor length. 888 40

The effects of insulin and the insulin mimetic agent "vanadate" were studied on the activities of alanine aminotransferase, aspartate aminotransferase, glutamate dehydrogenase and arginase in the cytosolic and the mitochondrial fractions of the kidney in control and alloxan induced diabetic rats. An enhancement in the activities of these enzymes were noted in both the fractions of diabetic kidney. Vanadate treatment (0.6 mg/ml in drinking water) of alloxan induced diabetic rats restored the activities of these enzymes almost completely in the cytosolic and partially in the mitochondrial fractions. Vanadate treatment also normalized hyperglycaemia without altering the depressed levels of insulin secretion in diabetic rats. The effect of insulin treatment was found to be the same as that of vanadate in diabetic rats.
Biochem Mol Biol Int 1996 Nov
PMID:Effects of vanadate and insulin on the activities of selected enzymes of amino acid metabolism in alloxan diabetic rat kidney. 895 44

Citrate production is a major physiological function of the prostate that is regulated by testosterone and prolactin. Mitochondrial aspartate aminotransferase (mAAT) is a key enzyme in the metabolic pathway of prostate citrate production. In addition, prolactin stimulates expression of mAAT in the rat lateral prostate. In this report we establish the role of prolactin in the regulation of mAAT in two prostate cancer cell lines, LNCaP and PC-3. LNCaP cells respond to hormonal stimulation with increased secretion of prostate specific products. PC-3 cells, on the other hand, are testosterone independent and apparently do not respond to other growth factors either. Results showed that both LNCaP and PC-3 cells responded to prolactin with increased mAAT activity and an increased steady state level of mAAT mRNA. Prolactin also increased protein kinase C (PKC) activity in both these cell lines. Treatment of LNCaP and PC-3 cells with the phorbol ester 12-O-tetradecanoylphorbol (TPA) caused the same effect on mAAT activity and mRNA level as prolactin. The results suggest that the diacylglycerol-PKC signal transduction system mediates the prolactin effect on mAAT. In addition, these results also show that the prolactin effect on mAAT is independent of androgens since PC-3 cells reportedly lack androgen receptor expression. Thus, these results provide evidence that prolactin is a physiological regulator of prostate function in human as well as rat prostate. In addition, the results also show that though prostate cancer cells are androgen independent, they remain responsive to prolactin. This could have important implications for the treatment and management of prostate cancer.
Mol Cell Endocrinol 1997 Mar 14
PMID:Prolactin regulation of mitochondrial aspartate aminotransferase and protein kinase C in human prostate cancer cells. 909 97

Effects of acute physical exercise on the acetaminophen-induced hepatotoxicity were examined in adult female rats. Rats were forced to move at a speed of 10 m/min for 2 hr in a rotating cage. Immediately following the exercise bout rats were treated with acetaminophen (APAP; 700 mg/kg, i.p.). The physical exercise enhanced the hepatotoxicity of APAP as shown by increases in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities measured 24 hr following the treatment. A significant decrease in hepatic glutathione (GSH) was observed in the rats forced to exercise suggesting that the enhancement of APAP hepatotoxicity was associated with the depression of this endogenous tripeptide. The role of adrenergic stimulation in the exercise-induced hepatic GSH depression was examined by pretreating the animals with a receptor specific adrenergic antagonist, such as prazosin HCl (15 mg/kg, i.p.), propranolol HCl (15 mg/kg, i.p.), and yohimbine HCl (15 mg/kg, i.p.) 15 min prior to the exercise bout, but neither of the antagonists prevented the GSH depression. Administration of alpha-tocopherol acetate (450 mg/kg/day for 3 days and 150 mg/kg on day 4, i.p.) did not affect the exercise-induced GSH depression or lipid peroxidation in liver homogenates as determined by increases in malondialdehyde formation. These results suggest that neither adrenergic stimulation nor oxidative stress plays a significant role in the enhancement of APAP hepatotoxicity and hepatic GSH depression induced by acute physical exercise.
Res Commun Mol Pathol Pharmacol 1997 Apr
PMID:Potentiation of acetaminophen hepatotoxicity by acute physical exercise in rats. 917 66

Injection of guinea pigs with a single dose of Escherichia coli lipopolysaccharide (3.2 mg/100 g) induces a reversible endotoxic shock that was evaluated by measuring plasma glucose levels and aspartate aminotransferase activity at 24 h after lipopolysaccharide injection. The hypoglycaemia and the increase in plasma aminotransferase activity observed, correlated with the alterations found during the recovery phase of endotoxic shock. When lipid peroxidation and some antioxidant systems were measured in lungs from treated animals, we only found differences in ascorbic acid content, that was decreased by 50%. Lipopolysaccharide treatment results in a depression of pulmonary phosphatidylcholine synthesis, that correlates with the surfactant deficiencies associated with respiratory illnesses in septic shock. Guinea pigs fed on a diet with a low content in ascorbic acid were more sensitive to endotoxin. In these animals we found no detectable levels of ascorbic acid in lung, whereas both vitamin E lung levels and pulmonary phosphatidylcholine synthesis were significantly decreased. Our results point out the significance of ascorbic acid in the protection against oxidative lung injury associated to endotoxaemia, and validate our shock model for further studies on the mechanisms of this pathological condition.
Mol Cell Biochem 1997 Oct
PMID:Impaired phosphatidylcholine biosynthesis and ascorbic acid depletion in lung during lipopolysaccharide-induced endotoxaemia in guinea pigs. 935 41

Bacteriocytes harbouring Buchnera endosymbionts were isolated from young and old aphids, Acyrthosiphon pisum, and their mRNA populations were examined by the differential cDNA display and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) technique. It was suggested that several gene products are produced when the symbiotic system is well organized in the young insect, whereas others are produced after the system becomes degenerate in old aphids. Among the gene products that were actively synthesized in the symbiotic system of the young host were putative aspartate aminotransferase, homoserine kinase and N-acetylglutamate synthase. These findings were consistent with the hypothesis that the symbiotic system utilizes glutamate to produce essential amino acids.
Insect Biochem Mol Biol 1997 Dec
PMID:Differential display of mRNAs related to amino acid metabolism in the endosymbiotic system of aphids. 956 46


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>