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1.
《The International journal of biochemistry》1993,25(4):557-566
- 1.1. Particulate guanylate cyclase and receptors for E. coli heat-stable enterotoxin were solubilized from the rat intestinal cytoskeletal compartment using Lubrol-PX and KC1.
- 2.2. Thirty to forty percent of the ST receptor and guanylate cyclase activities were extracted from the lipid layer with Lubrol-PX alone.
- 3.2. Seventy percent of the remaining activities were solubilized from the cytoskeleton with Lubrol-PX and KCl.
- 4.3. Guanylate cyclase solubilized from either compartment exhibited similar reaction kinetics.
- 5.4. Both high- and low-affinity classes of ST receptors were solubilized from the lipid and cytoskeleton compartments.
- 6.5. In the presence of ATPγS, ST selectively activated the guanylate cyclase solubilized from the cytoskeleton compared to that solubilized from the lipid bilayer.
- 7.6. Crosslinking experiments demonstrated a preferential solubilization of the 130 kDa receptor subunit from the cytoskeleton and the 56 kDa subunit from the lipid bilayer.
- 8.7. Development of a procedure to solubilize ST receptors and guanylate cyclase from the intestinal membrane cytoskeleton will permit purification and further detailed studies of the coupling of these activities.
2.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1991,98(4):805-808
- 1.1. Adenylate cyclase activity was assayed in the optic lobe of Octopus vulgaris.
- 2.2. Both octopamine and dopamine stimulate the octopus adenylate cyclase, apparently by competing with the same receptor site.
- 3.3. (±)-2-Amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene-HBr (6,7-ADTN) and a number of phenylethanolamine derivatives stimulate the octopus adenylate cyclase activity.
- 4.4. The dopamine D-1 antagonists R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-HCl (SCH-23390) and (±)-7-bromo-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-HCl (SKF-83566) are unable to antagonize the effects of dopamine and octopamine, and similarly ineffective is the agonist (±)-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol-HCl (SKF-38393).
- 5.5. No detectable binding of labelled SCH-23390 occurs on membrane preparations from octopus optic lobe.
3.
《Insect Biochemistry》1990,20(6):639-644
Evidence for the involvement of cAMP in the triggering of meiotic reinitiation by ecdysone in vitellogenic oocytes of Locusta migratoria is presented:
- 1.(1) the intracellular concentration of cAMP decreases significantly (by 40%) in the oocytes at the time when meiotic reinitiation is induced;
- 2.(2) drugs which increase the concentration of cAMP antagonize the stimulatory action of ecdysone;
- 3.(3) ecdysone treatment of excised oocytes is followed by a decrease in intra-cellular cAMP;
- 4.(4) ecdysone reduces the adenylate cyclase activity when added to plasma membrane preparations in vitro.
4.
《Comparative biochemistry and physiology. A, Comparative physiology》1992,101(4):823-826
- 1.1. Adenylate cyclase activity was determined in membranes of white and brown adipose tissue (WAT and BAT, respectively) from rats fed a high-energy diet (EXP group) vs those fed a nutritionally balanced one (CON group).
- 2.2. The isoproterenol- and guanine nucleotide-induced adenylate cyclase activity in WAT membranes of EXP rats was lower than that in CON rats.
- 3.3. Relative adenylate cyclase activity in like treated BAT membranes was higher in EXP than in CON rats.
- 4.4. It is concluded that feeding high-energy diets to rats induces similar post-receptor modifications of adenylate cyclase as found in genetic obese rodents.
5.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1981,68(1):153-156
- 1.1. The sterol composition of Condylactis aurantiaca and Cereus pedunculatus (phylum Coelenterata, class Anthozoa, order Actiniaria) was investigated by silver nitrate-silica gel column chromatography, combined gas chromatography-mass spectrometry and NMR.
- 2.2. Sea anemones contained Δ3-sterols accompanied by small amounts of Δ5.7-sterols and ring saturated sterols.
- 3.3. Sterols with 27 carbon atoms are predominant and cholesterol is the principal sterol, followed by 24-methylenecholesterol.
- 4.4. A 4-methyl ring saturated sterol, identified as 4,24-dimethyl-5α-cholest-24(28)-en-3β-ol, occurs in small amount in Actiniaria, accompanied by the corresponding 4-demethylstanol.
6.
《Comparative biochemistry and physiology. A, Comparative physiology》1987,86(3):455-459
- 1.1. The addition of cAMP to stimulating solutions of NaCl, fructose (furanose sugar), sucrose, or glucose (pyranose sugars) decreases the responsiveness of labellar chemosensilla in Phormia.
- 2.2. The addition of ATP, while decreasing the responsiveness to NaCl or fructose enhances the responsiveness to glucose and sucrose.
- 3.3. The inhibiting effect of ATP on NaCl or fructose responses is suppressed by GDPßS, an inhibitor of adenylate cyclase (and thus of cAMP synthesis); moreover GDPßS further enhances the increase in response due to ATP when added to the sucrose or glucose solutions.
- 4.4. Results suggest a possible involvement of cAMP and ATP in the taste reception mechanism in the blowfly.
7.
《Comparative biochemistry and physiology. C: Comparative pharmacology》1991,98(1-2):271-275
- 1.1. The modulation of lipid dynamics and lipid protein interactions were studied in rat brain synaptosomal plasma membranes (SPM) up to 24 hr after exposure to cadmium (Cd).
- 2.2. The activity of acetylcholinesterase and adenylate cyclase showed a considerable decrease after 6 hr of Cd exposure, followed by a progressive increase up to 24 hr.
- 3.3. SPM chemiluminescence showed a maximum decrease at 12 hr, demonstrating a considerable increase in lipid peroxidation.
- 4.4. SPM of Cd-exposed animals showed a statistical significant increase in fluorescence anisotropy parameter [(r0/r) — 1]−1 at 18 and 24 hr compared to SPM of the control, indicating a decrease of membrane fluidity.
8.
《The International journal of biochemistry》1981,13(5):591-602
- 1.1. A choriolytic enzyme was isolated from the hatching medium of the pike, Esox lucius.
- 2.2. The enzyme is defined as hatching enzyme.
- 3.3. The molecular weight of the enzyme is 24,000.
- 4.4. The enzyme is a glycoprotein containing 2% carbohydrate.
- 5.5. Its isoelectric point is 6.5.
- 6.6. The pH optimum is around pH 8.
- 7.7. The enzyme molecule contains two disulfide bonds but no free cysteine.
- 8.8. Inhibitor studies and metal analysis show that the enzyme is a zinc-metalloprotease.
9.
10.
《The International journal of biochemistry》1984,16(1):117-120
- 1.1. The specific activity of GMP synthetase was measured in several human tissues and found to be highest in cultured skin fibroblasts, followed by bone marrow, leukocytes, erythrocytes. placenta, and liver.
- 2.2. The enzyme from fibroblasts was purified approximately 50-fold by ammonium sulfate fractionation and gel filtration.
- 3.3. The Km values were determined to be 4.9μM for XMP, 270μM for ATP. and 340 μM for glutamine.
- 4.4. Ammonium sulfate could replace glutamine as the amino donor but was much less efficient.
- 5.5. The enzyme was specific for ATP as the energy source.
- 6.6. Unlike the calf thymus enzyme, the human enzyme has no requirement for a reduced sulfhydryl compound.
- 7.7. Human GMP synthetase is inhibited by ATP, dATP, azaserine, and hydroxylamine.
11.
《The International journal of biochemistry》1993,25(12):1775-1784
- 1.1. To characterize an enzyme which metabolizes retinal in liver microsomes, several properties of the enzymatic reaction from retinal to retinoic acid were investigated using rabbit liver microsomes.
- 2.2. The maximum pH of the reaction in the liver microsomes was 7.6.
- 3.3. The Km and Vmax values for all-trans, 9-cis and 13-cis-retinals were determined.
- 4.4. The reaction proceeded in the presence of NADPH and molecular oxygen.
- 5.5. The incorporation of one atom of molecular oxygen into retinal was confirmed by using oxygen-18, showing that the reaction comprised monooxygenation, not dehydrogenation.
- 6.6. The monooxygenase activity was inhibited by carbon monoxide, phenylisocyanide and antiNADPH-cytochrome P-450 reductase IgG, but not by anti-cytochrome b5 IgG.
- 7.7. The enzymatic activity inhibited by carbon monoxide was photoreversibly restored by light of a wavelength of around 450 nm.
- 8.8. The retinal-induced spectra of liver microsomes with three isomeric retinals were type I spectra.
- 9.9. The microsomal monooxygenase activity induced by phenobarbital or ethanol were more effective than that by 3-methylcholanthrene, clotrimazole or β-naphthoflavone.
- 10.10. These results showed that the monooxygenase reaction from retinal to retinoic acid in liver microsomes is catalyzed by a cytochrome P-450-linked monooxygenase system.
12.
《Ethology and sociobiology》1988,9(5):319-324
This paper comments on: Low, B. S., Alexander, R. D., and Noonan, K.M. Human hips, breast, and buttocks: Is fat deceptive? Ethology and Sociobiology 8: 249-247, 1987. In it I argue that:
- 1.1. Sexual selection has probably not been the most important selection pressure on
- 2.female human body shape.
- 3.2. Male humans in different cultures find different aspects of the female body attractive
- 4.and therefore are unlikely to have exerted consistent directional sexual selection on
- 5.the female body.
- 6.3. Breast size is not correlated with lactation success.
- 7.4. Visible hip width is not correlated with parturition success.
- 8.5. Women would lower their fitness if they tried to deceive men about their internal
- 9.pelvic dimensions.
- 10.6. There are many alternative hypothesis to explain the existence of fat onwomen's
- 11.breast, hips, and buttocks.
13.
《The International journal of biochemistry》1991,23(12):1445-1451
- 1.1. An alkaline p-nitrophenylphosphate phosphatase has been purified 440-fold from extracts of Hatobacterium halobium.
- 2.2. The enzyme has an apparent molecular weight of 24,000.
- 3.3. A Km value for p-nitrophenylphosphate of 1.12mM has been found under optimal conditions.
- 4.4. The enzyme is selectively activated and stabilized by Mn2+.
- 5.5. It requires high salt concentrations for stability and maximum activity.
- 6.6. It displays an unusual restricted substrate specificity of 25 phosphate esters tested, only phosphotyrosine and casein were hydrolysed besides p-nitrophenylphosphate.
14.
《Comparative biochemistry and physiology. A, Comparative physiology》1979,62(2):363-370
- 1.1. The unidirectional transepithelial fluxes of L-phenylalanine, β-methyl-D-glucoside and sodium ions across emusculated sheets of tench mid-intestine were determined in flux chambers.
- 2.2. No net sodium flux was detectable, but phenylalanine was preferentially transferred from the mucosal to the serosal fluid.
- 3.3. There was also a net movement of β-methyl-glucoside towards the serosal medium, but it was much smaller than that of phenylalanine.
- 4.4. This transport was accompanied by an accumulation of each substrate from the mucosal medium into the tissue to a similar level and against a concentration gradient.
- 5.5. The poor transfer of the monosaccharide into the serosal medium could therefore be attributed to a low permeability of the baso-lateral membrane of the enterocyte for this substance.
- 6.6. The influx of L-phenylalanine and of β-methyl-d-glucoside into the epithelial cells of tench midintestine was examined by incubating slices of emusculated intestine in radioactively-labelled solutions of the substrate for 2 min.
- 7.7. The steady-state uptake was assessed after similar incubations lasting 45 min.
- 8.8. Phenylalanine influx obeys the Michaelis-Menten equation with a Km of 2.9 mM and is dependent on the presence of sodium ions in the incubation medium.
- 9.9. β-Methyl-glucoside influx reveals the same characteristics with a Km of 2.0 mM but a considerably lower Vmax; in addition, it is inhibited by galactose.
- 10.10. The influx of both substrates is reduced by harmaline, which also inhibits the uptake of radioactive sodium by this preparation.
- 11.11. The steady-state uptake of β-methyl-glucoside is also inhibited by ouabain and by 2.4-dinitrophenol.
- 12.12. These results suggest that the mechanisms for sodium-dependent influx of monosaccharides and neutral amino-acids in the tench intestine are similar to those found in mammalian tissues.
- 13.13. The principal difference appears to involve the release of monosaccharides across the baso-lateral membrane of the enterocyte.
15.
《Comparative biochemistry and physiology. A, Comparative physiology》1978,59(3):407-410
- 1.1. Insulin stimulated intracellular accumulation of α-amino-isobutyric acid (AIB) in kidney cortex slices from young lambs and piglets.
- 2.2. The effect was similar in the absence or presence of glucose.
- 3.3. The induction of the stimulatory effect on renal AIB transport was blocked by cycloheximide. an inhibitor of protein synthesis.
- 4.4. The insulin stimulation of intracellular AIB accumulation is due to an increased influx and not to a reduced efflux of AIB.
- 5.5. Analysis of transport kinetics for AIB showed that insulin increased Vmax but did not change Km.
- 6.6. It is concluded that insulin stimulates uptake of certain neutral amino acids into kidney cortex cells in young animals.
- 7.7. The effect on renal amino acid transport appears to be mediated through increased synthesis of a membrane carrier.
16.
《The International journal of biochemistry》1994,26(3):375-380
- 1.1. A purification procedure for a thioredoxin from the extremophilic archaeon Sulfolobus solfataricus is described.
- 2.2. The thioredoxin is active in the dithiothreitol-dependent reduction of insulin disulfide bonds.
- 3.3. The thioredoxin is a monomer of 24,800 Da; it is an acidic protein with a pi of 4.5.
- 4.4. The protein is stable to heating for 3 hr at 90°C.
- 5.5. The amino acid composition of S. solfataricus thioredoxin is reported.
17.
《Comparative biochemistry and physiology. A, Comparative physiology》1986,83(3):489-493
- 1.1. Fundamental chitin digestion characteristics of Crassostrea virginica crystalline style were investigated.
- 2.2. Optimum temperature and pH were 34°C and 4.8. respectively.
- 3.3. The colloidal regenerated chitin (0.56mol/0.5 ml: GlcNAc equivalents) was saturating under all enzyme levels encountered.
- 4.4. There was no evidence of end product inhibition, even after 100 hr incubation.
- 5.5. Calculated Km for the chitinase complex was 1.19mM when determined using a 30 min assay, but was only 0.70 mM when determined using a 4.6 hr assay.
- 6.6. Both Km values are lower than reported for similar assays in other molluscs and for most bacteria.
- 7.7. Effect of substrate preparation on the kinetics are discussed.
- 8.8. Eight peaks of chitinase activity were resolved by DEAE-Fractogel ion exchange chromatography.
18.
《The International journal of biochemistry》1985,17(3):341-345
- 1.1. A new tetralysine endopeptidase from Escherichia coli AJ005 has been purified about 135-fold.
- 2.2. The peptidase seems to be specific to tetralysine among lysine homopolymers.
- 3.3. The optimal pH was about 7.5
- 4.4. The activity was inhibited by KCN but not inhibited by soybean trypsin inhibitor.
- 5.5. The apparent Km value was 2.5 × 1O−3 M for tetralysine.
19.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1983,74(2):291-293
- 1.1. The hydrolysis of glycol chitin preparations by several β-N-acetylglucosaminidases was monitored colorimetrically with the potassium ferriferrocyanide reagent.
- 2.2. Glycol chitin samples from crab and insect sources varied considerably in chemical composition and susceptibility to enzymatic hydrolysis.
- 3.3. Insect endochitinase preferred crab glycol chitin as substrate while hen's egg white lysozyme preferred commercial glycol chitin.
- 4.4. Insect glycol chitin was well hydrolyzed by both enzymes.
- 5.5. Insect exochitinase did not digest glycol chitin.
20.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1986,83(4):783-785
- 1.1. Seven natural populations of Dacus dorsalis were analyzed for a dimeric esterase by means of horizontal starch-gel electrophoresis.
- 2.2. The electrophoretic phenotypes were governed by nine codominant Est-D alleles.
- 3.3. The commonest allele in all seven population samples was Est-D100 which encoded an electrophoretic band with intermediate mobility.
- 4.4. The distribution of EST-D phenotypes were in accordance with Hardy-Weinberg expectations.
- 5.5. There was no geographic variation in the distribution of Est-D alleles.