Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe a column-chromatographic method for separating the mitochondrial and cytoplasmic isoenzymes of aspartate aminotransferase in human serum. Bed height of the ion exchanger, pH, and salt concentrations in the eluting buffers are shown to be variables affecting the separation of the isoenzymes. Under the optimized conditions selected for this study, a 30% increase in volume was observed in one fraction, associated with changing the salt concentration of the eluting buffer and attributed to a contraction of the DEAE-Sephadex A-50. Elution profiles (enzyme activity vs. fraction number) were examined with highly purified mitochondrial and cytoplasmic isoenzymes of human origin in bovine serum albumin and human serum. Recovery of the enzyme in the eluted fractions averaged 102% (SD, 2.0%) for specimens prepared from the purified isoenzymes and 104% (SD, 10.7%) for 38 human serum specimens. The separation technique showed linearity to catalytic concentrations in excess of 200 U/liter (reaction temperature 30 degrees C) for each isoenzyme. Additional information is presented regarding among-day precision and the effect of specimen dilution.
...
PMID:Column-chromatographic separation of isoenzymes of aspartate aminotransferase. 2 23

Toxicosis was induced in pregnant heifers by feeding 25,000 mg/head/day of FireMaster BP-6, a commercial blend of polybrominated biphenyls (PBB). The PBB feeding decreased dry matter intake approximately 50% by 4 days exposure. Emaciated animals became anorexic a few days prior to death at 33 to 66 days. Weight losses of heifers average 80 kg. Other clinical signs observed were dehydration, diarrhea, excessive salivation and lacrimation, fetal death, abortion, and general depression as evidenced by depressed heart and respiratory rates. Clinical signs were apparent after 10 days exposure and progressively intensified along with loss of condition until death. Clinicopathologic changes included significantly increased serum glutamic-oxaloacetic transaminase and decreased serum calcium by 30 days exposure. Lactate dehydrogenase, urea nitrogen, and bilirubin were elevated, and serum albumin decreased by 36 to 40 days. Principal urine changes were decreased specific gravity and moderate proteinuria. Pregnant heifers fed 0.25 or 250 mg/head/day for 60 days and nonpregnant heifers fed 250 mg/head/day for 180 days displayed neither clinical signs nor clinicopathologic changes indicating adverse effects from PBB exposure. Post-exposure, all heifers exposed to PBB for 60 days calved normally with zero calf mortality and were successfully rebred. Milk production was not different from control animals. Birth weights of calves from dams exposed to 250 mg PBB/head/day were significantly greater than calves of dams exposed to 0 mg or 0.25 mg/head/day. PBB exposure of dams produced no detrimental effects on calves as indicated by clinical signs, clinicopathologic changes, or performance.
...
PMID:Effects of PBBs on cattle. I. Clinical evaluations and clinical chemistry. 21 5

The diagnosis of acute superior mesenteric artery occlusion in the dog has been achieved in every case by isotope scanning of the abdomen using technetium-labelled red cells or technetium-labelled human serum albumin. The white cell count is also significantly elevated, but the changes in the levels of the enzymes CPK, LDH, AST and serum amylase are not specific for actue mesenteric ischaemia. In the human the presence of a normal gut circulation can be demonstrated by isotope scanning provided that the patient is not severely shocked. The presence of a normal gut circulation as shown on the scintigram conclusively eliminates the possibility of acute main trunk occlusion of the superior mesenteric artery. This should be of help in differentiating acute occulusive mesenteric ischaemia from other causes of the acute abdomen. Abdominal scintiscanning is complementary to angiography, which still remains the most precise means of diagnosing acute mesenteric ischaemia. Although the abdominal scintigram is more limited in its application and is not as accurate as angiography, it is quicker to perform, non-invasive, and entirely safe. Abdominal scintiscanning is an excellent screening test to be used in patients suspected of suffering from acute occlusive mesenteric ischaemia.
...
PMID:The early diagnosis of acute occlusive mesenteric ischaemia: experimental results and clinical applications. 28 87

Isolated rat livers were perfused at 35 degrees C with bovine serum albumin (40 g/l) in Krebs Ringer bicarbonate buffer, or with the same solution containing insulin (0.22 x 10(-6) mol/l), hydrocortisone (0.068 x 10(-3) mol/l), or both hormones together. Observations on the synthesis of bile and on perfusate levels of potassium, aspartate aminotransferase, urea and glucose showed that the presence of insulin and/or hydrocortisone had no beneficial effect on the perfused rat liver in vitro. There is little justification of the isolated liver.
...
PMID:The effect of insulin and hydrocortisone on the isolated rat liver. 28 8

Eight different pools of purified human mitochondrial and cytoplasmic isoenzymes of aspartate aminotransferase were prepared, to examine the effects of the following matrix variables: the matrix support material (bovine serum albumin and polyvinylpyrrolidone), endogenous pyridoxal concentration, and azide as an antimicrobial preservation. Storage temperatures of 25 and 37 degrees C were used as a rapid and convenient means of accelerating the degradation process. Activity of the enzyme was measured with and without pyridoxal in the reaction solution. We found that the mitochondrial isoenzyme was consistently more labile than the cytoplasmic isoenzyme under identical storage conditions. Both isoenzymes were more stable in matrixes containing bovine serum albumin than in those containing polyvinylpyrrolidone. No apparent difference in the stability of either isoenzyme was observed at matrix pyridoxal concentrations of 15 micromol/L and 150 micromol/L. Only the mitochondrial isoenzyme in matrixes containing bovine serum albumin and 15 micromol of pyridoxal per liter had increased activity (about 9%) when pyridoxal was added to the enzymatic reagent. The amount of activity in reconstituted specimens did not apparently change after 72 h at 4 degrees C.
...
PMID:Relative stabilities of purified human mitochondrial and cytoplasmic isoenzymes of aspartate aminotransferase in lyophilized materials. 43 29

Three groups of isolated rat livers were perfused at 35 C with Krebs-Ringer bicarbonate buffer containing commercial bovine serum albumin (BSA) which had been purified by gel filtration on a column of Sephacryl S-200 and used within 12 hr of purification, or BSA which had been purified by gel filtration and stored at -70 C until used. The ability of livers to produce bile, retain potassium, and to maintain a constant level of glucose in the perfusate was greatly improved in the presence of purified albumin which had not been frozen. Such livers also showed the highest rates of urea synthesis, but the rate of release of aspartate aminotransferase (GOT) from cells and the bile salt content of the bile produced were similar to those found with unpurified BSA. Livers perfused with purified albumin which had been stored in the frozen state were slightly inferior to those perfused with nonfrozen albumin in their ability to produce bile and urea, to retain potassium and GOT within cells, and to maintain a constant concentration of glucose in perfusates. The concentration of bile salts in the bile produced by this group was also lower than that found with the other two groups. Overall, isolated rat livers benefited from perfusion with purified albumin, although freeze storage of this material rendered it slightly inferior to the nonfrozen material in its ability to support the liver.
...
PMID:Improved performance of the isolated rat liver when perfused with purified bovine serum albumin. 46 29

Admission serum triiodothyronine (T3) values in 124 patients hospitalized for alcoholic liver disease were correlated with clinical and laboratory indices of liver function and commonly used determinants of thyroid function. Patients with low admission serum T3 levels had significant alterations in serum albumin, bilirubin, prothrombin time, and alkaline phosphatase associated with clinical signs of portal hypertension and collateral circulation, with little difference in serum glutamic-oxaloacetic transaminase, serum gamma glutamyl transpeptidase, or serum ornithine carbamyl transferase. This group also had a significant decrease in free T3 index despite an increase in T3 uptake; the slight reduction in total thyroxine (T4) was associated with an increase in free T4 index and no change in serum thyrotropin (TSH). For patients with alcoholic liver disease, low admission serum T3 and free T3 index values when accompanied by normal serum T4, free T4 index, and TSH levels appear to be indicative of severe liver dysfunction and increased mortality risk.
...
PMID:Serum triiodothyronine and other clinical and laboratory indices of alcoholic liver disease. 46 36

The effect of danazol in a dose of 600 mg a day was studied in 20 women with moderate or severe endometriosis. The clinical effect was found to be excellent and repeat laparoscopy after about 6 months treatment revealed a marked regression in all patients with only small residual foci of endometriosis in two of them. The side effects were few. The metabolic studies revealed a significant increase in serum aspartate aminotransferase (AST), serum alanine aminotransferase (ALT), serum potassium, serum albumin and serum creatinine, but a significant decrease in serum gamma glutamyl transpeptidase (GT). Serum sodium showed no alteration. A longitudinal study of basal plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and their responses to 25 microgram gonadotrophic releasing hormone (GnRH) i.v. as well as basal plasma levels of oestradiol, oestrone, progesterone and prolactin was performed. During treatment with danazol (600 mg a day) basal levels of LH, FSH, oestradiol, oestrone and progesterone were low but did not differ from the levels found in the early follicular phase of the menstrual cycle. On the other hand the pituitary response to GnRH was significantly greater for both LH and FSH than observed during the early follicular phase. These conflicting results are discussed. It seems that danazol inhibits the pituitary secretion of biologically active LH and FSH and this action is responsible for the decreased ovarian steroid secretion. Whether the atrophy of the uterine and ectopic endometrium is an effect of the reduced oestradiol levels or is a direct effect of danazol on endometrial oestrogen receptors, or a combination of both modes of action, is not clear.
...
PMID:Hormonal, metabolic and clinical effects of danazol in the treatment of endometriosis. 53 48

Holotyrosine phenol-lyase (EC 4.1.99.2), a pyridoxal-5'-phosphate (PLP)- requiring enzyme, was shown to rapidly dissociate when injected into BDF1 mice. The holoenzyme dissociated when incubated in plasma but not 0.01 M potassium phosphate (pH 7.4) buffer at 37 degrees C. A nonspecific alkaline phosphatase from calf intestine was found to inactivate the holoenzyme at pH 7.4 and 37 degrees C. This inactivation was inhibited in the presence of 0.5 M potassium phosphate buffer. Two other PLP-requiring enzymes, aspartate aminotransferase (EC 2.6.1.1), and alanine aminotransferase (EC 2.6.1.2) were inactivated by alkaline phosphatase in a similar manner. Incubation of holotyrosine phenol-lyase in the presence of bovine serum albumin also resulted in a reduction of holoenzyme activity but partially protected the enzyme from inactivation by alkaline phosphatase. A nuclear fraction having PLP-hydrolyzing activity also inactivated holotyrosine phenol-lyase. A regulatory function for alkaline phosphatase in the metabolism of PLP-requiring enzymes is suggested by these data.
...
PMID:Albumin and alkaline phosphatase as factors involved in the regulation of tyrosine phenol-lyase activity. 65 5

The Center for Disease Control (CDC), the New York State Department of Health (NYSDH), the College of American Pathologists, and 23 manufacturers of diagnostic products participated in an interlaboratory study of aspartate aminotransferase (EC 2.6.1.1) methodologies. Six different lyophilized materials were prepared and characterized and then distributed to 293 laboratories for aspartate aminotransferase measurements. The specimens included one human serum; four catalytic concentrations of the cytoplasmic isoenzyme, two purified from human erythrocytes, and two from porcine heart; and one matrix bovine serum albumin (30 g/liter) blank. The purified isoenzymes were prepared in the matrix. We present data on Michaelis parameters (Km and Vmax), Arrhenius plots, activation with pyridoxal 5-phosphate, vial-to-vial variability, and stability on reconstitution. The 281 responses showed that most of the laboratories used NADH-detection methods (91.1%), monitored at 340 nm (79.4%), and reported results in U/liter (89.4%). The percentage of laboratories reporting use of reaction temperatures of 30 and 37 degrees C was evenly divided, i.e., 42.7 and 42%, respectively. Analytical values reported by participating laboratories were categorized by reporting temperature, instrument, and method. Results were most consistent for a selected group of laboratories that supplemented optimized reaction solutions with pyridoxal 5-phosphate.
...
PMID:An interlaboratory study of measurement of aspartate aminotransferase activity with use of purified enzyme materials. 65 80


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

---