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1.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1993,104(2):281-285
- 1.1. The diffusional water permeability (Pd) of rabbit red blood cell (RBC) membrane has been monitored by a doping nuclear magnetic resonance (NMR) technique on control cells and following inhibition with p-chloromercuribenzene sulfonate (PCMBS).
- 2.2. The values of Pd were around 6.3 × 10−3 cm/sec at 15°C, 7.0 × 10−3cm/sec at 20°C, 8.0 × 10−3 cm/sec at 25°C, 9.1 × 10−3 cm/sec at 30°C and10.7 × 10−3 cm/sec at 37°C.
- 3.3. Systematic studies on the effects of PCMBS on water diffusion indicated that the maximal inhibition was reached in 15 min at 37°C with 0.5 mM PCMBS.
- 4.4. The values of maximal inhibition were around 71–74% at all temperatures.
- 5.5. The basal permeability to water was estimated as 1.6 × 10−3cm/sec at 15°C, 2.0 × 10−3cm/sec at 20°C, 2.4 × 10−3cm/sec at 25°C, 2.6 × 10−3cm/sec at 30°C, and 3.1× 10−3 cm/secat 37°C.
- 6.6. The activation energy of water diffusion was around 18 kJ/mol and increased to 27 kcal/mol after incubation with PCMBS in conditions of maximal inhibition of water diffusion.
- 7.7. The membrane polypeptide electrophoretic pattern of rabbit RBCs has been compared with its human counterpart.
- 8.8. The rabbit membrane contained a higher amount of spectrin (bands 1 and 2), while the band 6 (glyceraldehyde-3-phosphate dehydrogenase) was markedly less intense.
- 9.9. Considerable differences in the electrophoretic patterns of the two sources of RBC membranes appeared in the bands migrating in the band 4.5 region and in front of band 7, where some polypeptides were apparent in higher amounts in the rabbit RBC membrane.
2.
《The International journal of biochemistry》1994,26(9):1103-1109
- 1.1. Adenylylation, a posttranslational modification of proteins, was investigated in saponin-permeabilized acinar cells of the rat parotid gland.
- 2.2. When cells were incubated with [2,8-3H]ATP, several proteins, including a 26 kDa protein in the particulate fraction, were labeled.
- 3.3. Upon incubation of cells with [α-32P]ATP in the presence of cAMP and 3-isobutyl-lmethylxanthine, 32P-labeling of the 26 kDa protein was observed.
- 4.4. After treatment with snake venom phosphodiesterase, [32P]AMP was released from the 26kDa protein. Such release was not observed when cells were labeled with [γ-32P]ATP.
- 5.5. The 32P-labeling pattern of proteins with [α-32P]ATP was clearly different from that with [adenylate-32P]NAD+.
- 6.6. The results suggest that the 26 kDa protein is one of the adenylylation substrates in rat parotid acinar cells.
3.
《The International journal of biochemistry》1984,16(6):623-628
- 1.1. 3-hydroxykynureninase in human liver was present in cytosol and mitoehondria.
- 2.2. The cytosolic enzyme and mitochondrial enzyme had the same physiological and enzymic properties.
- 3.3. The enzyme had a mol. wt of 130,000 by gel filtration and isoelectric point of pH 5.9.
- 4.4. The enzyme was active for 3-hydroxykynurenine and kynurenine, and its activity ratio was 15:1. The apparent Km values of the enzyme were 7.7 × 10−5M for 3-hydroxykynurenine, 1.0×10−3M for kynurenine and 2.5 × 10−6M for pyridoxal 5'-phosphate with 3-hydroxykynurenine.
- 5.5. Some other properties of purified enzymes are described.
4.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1989,92(4):613-619
- 1.1. Five classes of sea bass serum lipoproteins were purified by single vertical spin ultracentrifugation and agarose column chromatography
- 2.2. VLDL, beta migrating, are the larger and less dense lipoproteins.
- 3.3. LDL are the more heterogeneous in size, ranging from 11 × 106 to 1 × 106.
- 4.4. HDL represent the predominant class which, on the basis of density and electrophoresis migration, is differentiated in three subclasses.
- 5.5. VHDL float at a density > 1.22 mg/ml, which corresponds to the density of the other serum lipoproteins. This subclass, with an apparent molecular weight of 1.5 × 105, resembles the albumin-like fatty acids binding proteins, shown in mammals and teleosts and absent in elasmobranchs.
5.
《Journal of insect physiology》1987,33(3):183-189
- 1.1. Increases in membrane conductance (gm) were induced by GABA in distal bundles 32, 33 and 34 of extensor tibiae muscles of the locust (Schistocerca gregaria).
- 2.2. Bath application of GABA (10−5−5 × 10−3 M) induced reductions in muscle fibre space constant (λ).
- 3.3. GABA (5 × 10−3 M) induced additional membrane conductance of 2.21 ± 0.03 × 10−6 S/mm, 0.38 ± 0.03 × 10−6 S/mm and 0.29 ± 0.06 × 10−6 S/mm on muscle bundles 34, 33 and 32 respectively. The greater sensitivity of muscle fibres in bundle 34 to GABA is due at least in part to a larger number of GABA receptors on bundle 34 muscle fibres.
- 4.4. The decrement of electrotonic potentials in the presence of GABA were measured over distances of both half fibre length and whole fibre length. Good agreement was obtained between changes in space constant produced by GABA using half fibre length and whole fibre length data.
- 5.5. By taking into account changes in space constant induced by GABA it was possible to demonstrate that presynaptic GABA receptors were involved in the inhibition of slow excitatory postsynaptic potentials by GABA.
- 6.6. “Slow” excitatory postsynaptic potentials recorded under current clamp were inhibited in a dose-dependent manner by GABA. This inhibition was not dependent on muscle-fibre GABA sensitivity and could not be completely accounted for by GABA-induced changes in the cable properties of the muscle fibres.
6.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1978,59(2):247-252
- 1.1. Lipoamide dehydrogenase was purified 1500-fold from mackerel dark muscle.
- 2.2. The enzyme was homogeneous as judged by acrylamide gel electrophoresis in the presence and absence of SDS.
- 3.3. Molecular weights of 102,000 and 55,000 were estimated for the native and denatured enzyme, respectively.
- 4.4. Optimal activity for the enzyme was obtained at around pH 5.7 and enhanced with citri acid.
- 5.5. Loss of activity was less than 5% by incubating the enzyme at 70°C for 20 min.
- 6.6. An apparent Km of 3.1 × 10−3 M was obtained for dl-lipoic acid and 1.5 × 10−5 M for NADH.
- 7.7. The properties of lipoamide dehydrogenase from mackerel dark muscle observed in this investigation were very similar to those reported for the enzyme from other sources.
7.
《Comparative biochemistry and physiology. A, Comparative physiology》1980,65(1):119-127
- 1.1. Freshwater gammarids from 900–1400 m depths lose Na at 1 atm, 4°C, while related shallow water gammarids are near neutral Na balance.
- 2.2. Na+ influx rates are similar at 1 atm, 4°C, for abyssal and shallow water gammarids of similar weight.
- 3.3. Na+ efflux is faster for abyssal gammarids than for comparable shallow water gammarids.
- 4.4. Compressing abyssal gammarids to 90–140 atm increases Na+ influx rates enough to restore neutral Na balance, while in shallow water crustaceans, compression decreases Na+ influx.
- 5.5. Na+ influx rates in Baikalian gammarids vary with the 0.55 power of weight.
- 6.6. The equation Fma × t = 1.3 × W0.55 μEq/hr/animal applies to freshwater crustaceans over the weight range from 0.03 to 35 g.
8.
《The International journal of biochemistry》1994,26(2):201-206
- 1.1. A non-radioisotopic method utilizing a biotin-avidin approach was used to characterize lactoferrin binding to the clonal MAC-T bovine mammary epithelial cell line.
- 2.2. Binding of lactoferrin to MAC-T cells and isolated membranes was specific and saturable.
- 3.3. Unlabeled lactoferrin competed for and displaced biotin-labeled lactoferrin from binding sites on mammary epithelial cells. In contrast, unlabeled transferrin did not compete.
- 4.4. Scatchard analysis of lactoferrin binding to MAC-T cell crude membranes was nonlinear, revealing two classes of binding sites with association constants (Ka) of 2.36 × 107 and 3.36 × 106M−1.
- 5.5. Binding of lactoferrin to MAC-T cells may be associated with the initial events which result in decreased MAC-T cell proliferation.
9.
《The International journal of biochemistry》1984,16(12):1217-1221
- 1.1. Primate liver lysosomal acid DNase is an endonucleolytic enzyme.
- 2.2. The enzyme has both 3'- and 5'-nucleotidohydrolase activities.
- 3.3. The oligonucleotides produced by DNase are polymers mainly about 30 mononucleotides long.
- 4.4. The Arrhenius plot shows a discontinuity with a transition temperature at 47°C, with an activation energy of 107 kJ/mol below and 67 kJ/mol above this temperature.
- 5.5. The activation enthalpy is 104kJ/mol and the entropy −0.498 kJ/mol/K.
- 6.6. The enzyme is subject to substrate inhibition and the Km value is 159 × 10−3mM DNA-P.
10.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1978,59(4):571-579
- 1.1. Ribosomes were purified from the oocysts of Eimeria tenella and characterized. Those in the unsporulated oocysts were mostly in the form of polysomes which became gradually dissociated during the early phase of sporulation and were mostly in the monomeric form in sporulated oocysts.
- 2.2. The monomeric E. tenella ribosome had the size of about 80S and consisted of 60 and 40S subunits. It was readily and completely dissociated to subunits at high potassium concentrations, and its subunits could not hybridize with those of chicken liver ribosome.
- 3.3. The E. tenella ribosomal RNA was estimated to have sedimentation coefficients of 5, 16 and 23S.
- 4.4. The E. tenella ribosomal proteins had a gel electrophoretic pattern similar to that of E. coli.
- 5.5. The in vitro polypeptide synthesis mediated by E. tenella ribosomes was inhibitable by tetracycline and chloramphenicol which are also active against the parasite in vivo.
- 6.6. Chloramphenicol bound to E. tenella ribosomes with a dissociation constant of about 10−5 M.
- 7.7. All the evidence demonstrates prokaryotic characteristics of the E. tenella ribosome and suggests that the parasite may be a primitive eukaryote.
11.
《The International journal of biochemistry》1981,13(3):373-379
- 1.1. Two cyclic AMP-dependent protein kinases—Fraction I and II—have been isolated from chick liver soluble preparation on DEAE-cellulose.
- 2.2. Both fractions have an apparent Km for ATP of 2 × 10−6M, are stimulated maximally by 5 × 10−8 M cyclic AMP and phosphorylate mainly basic proteins—histone and protamine.
- 3.3. They exhibit various pH values for optimal activity and show differences with respect to both sensitivity to NaCl and substrate specificity.
- 4.4. The heat-stable protein modulator inhibits the cyclic AMP-dependent protein kinase activity of both fractions, but with cyclic GMP one kinase is stimulated and the other inhibited.
- 5.5. Slight differences in histone triggered holoenzyme dissociation as well as the lack of difference between their ability for subunit reassociation do not allow to classify these isozymes as protein kinases of Type I and II, according to Corbin et al. (1975).
12.
《Comparative biochemistry and physiology. A, Comparative physiology》1983,74(2):289-293
- 1.1. 14C-dichlorofarnesoate permeated rapidly into Haemonchus contortus (infective juveniles) and Panagrellus redivivus (mixed cultures) and was strongly bound by hydrophobic association (Ks > 10−4M).
- 2.2. Uptake rose linearly with increases in temperature (5–38°C) and external concentration (C0; 0.07–2.15 × 10−4 M). Within 1 hr the internal concentration, C1 was >C C0.
- 3.3. The pH of the medium (6–8) did not affect uptake.
- 4.4. Efflux of dichlorofarnesoate was low: the half-time of release was > 18 hr.
- 5.5. The uptake curve approximated to the expression C1/C0 = a(1 − e−bt) with a and b as constants and t in hr.
- 6.6. These results clarify previous work on the inhibitory action of juvenile hormone on the development of nematodes.
13.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1978,59(2):237-242
- 1.1. Productivity of silk, properly fibroin, of the silkworm Bombyx mori was in proportion to the amount of RNA accumulation in the posterior division of silk gland.
- 2.2. DNA content of the silk gland of a line of high silk productivity was twice as much as that of low productivity. A DNA molecule can transcribe RNA, ranged from 3 × 106 to 6 × 106 molecules.
- 3.3. An application of actinomycin to larvae lowered an accumulation of RNA in the silk gland and resulted in a decrease of silk production.
- 4.4. Even under the upper limit of starvation by which the larvae complete their life, the silk gland kept a normal level of the DNA content, except that it lost the synthesizing activity of RNA.
- 5.5. Treatment of larvae with juvenile hormone occasionally induced another DNA replication of the silk gland.
14.
《Comparative biochemistry and physiology. A, Comparative physiology》1993,104(4):823-830
- 1.1. Indian River male broiler chickens growing from 7 to 28 days of age were fed diets containing 12, 18, 24 and 30% protein + 0 or 1 mg triiodothyronine (T3)/kg of diet to study energetic costs of lipogenesis and the use of various substrates for in vitro lipogenesis.
- 2.2. De novo lipid and CO2 production were determined in the presence of [1-14C]pyruvate, [2-14q]pyruvate, [3-14C]pyruvate, [2-14C]acetate and [U-14C]alanine.
- 3.3. Oxygen consumption was determined in mitochondrial preparations to estimate the energetic costs in expiants synthesizing lipid.
- 4.4. Radiolabeled CO2 derived from [1-14C]pyruvate was used as an estimate of coenzyme A availability in liver expiants. Lipids derived from [2-14C]pyruvate, [2-14C]acetate and [U-14C]alanine estimate relative substrate efficiency.
- 5.5. Labeled CO2 production from [1-14C]pyruvate was greatest in that group fed a 12% protein diet and least in the group fed a 30% protein diet.
- 6.6. In addition, T3 increased CO2 production from [1-14C]pyruvate.
- 7.7. The production of 14CO2 from the second carbon of pyruvate or acetate was increased by T3.
- 8.8. The low-protein diet (12% protein) increased (P <0.05) lipogenesis.
- 9.9. Adding T3 to the diets decreased carbon flux into lipid from all substrates, but increased CO2 production from all substrates without changing stage 3 and 4 respiration rates in mitochondrial preparations.
- 10.10. These observations imply that coenzyme A availability may have regulated de novo lipogenesis in the present study.
- 11.11. It was also concluded that previously noted effects of T3 on intermediary metabolism may involve metabolic pathways that do not involve changes in mitochondrial function.
15.
《The International journal of biochemistry》1982,14(10):915-920
- 1.1. Pentoxifylline (I) [3,7-dimethyl-1-(5-oxo-hexyl)-xanthine] (0–10−3M) inhibited the discocyte-echinocyte transformation caused by hyperosmolarity and improved the impaired filtrability of erythrocytes due to hyperosmolarity.
- 2.2. The ATP content of erythrocytes was increased at low concentrations (0–3 × 10−5M) of I. but decreased at high concentrations (3 × 10−5 M or above) of I.
16.
《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.
17.
《Comparative biochemistry and physiology. A, Comparative physiology》1986,83(3):457-460
- 1.1. The behavioural responses of the freshwater snail Biomphalaria glabrata to chemical gradients of sugars were investigated by means of diffusion olfactometers.
- 2.2. The snails proved very discriminating in their responses. Thus, only nine (39.1%) of the 23 sugars tested proved to be statistically significant attractants or arrestants. None proved to be statistically significant repellents.
- 3.3. Of all the sugars tested maltose proved to be the most potent attractant or arrestant. The lower threshold of response to this sugar lies between 5 × 10−6 and 5 × 10−7M.
- 4.4. The results are compared with those obtained for amino and carboxylic acids and their ecological relevance is discussed.
18.
《The International journal of biochemistry》1983,15(8):1059-1065
- 1.1. The metabolism of purine bases and nucleosides in cotyledons and embryonic axes of black gram (Phaseolus mungo L.) was studied.
- 2.2. A large portion of absorbed [8-14C]adenine, [8-14C]guanine and [8-14C]adenosine was salvaged in nucleotide and nucleic acid synthesis.
- 3.3. Most of the radioactivity of [8-14C]hypoxanthine and [8-14C]inosine was incorporated into allantoin and allantoic acid.
- 4.4. Activity of adenine phosphoribosyltransferase in enzyme extracts was much higher than that of hypoxanthme and guanine phosphoribosyltransferase(s).
- 5.5. Apparent activity of adenosine kinase was higher than that of inosine kinase. 6. NAD+-dependent xan thine dehydrogenase was detected in both cotyledons and embryonic axes of the seedlings.
- 6.7. The capacity of purine salvage was higher m 24 hr old cotyledons than 24 and 48 hr old embryonic axes. The reverse was observed concerning that of purine degradation.
19.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1980,65(3):447-453
- 1.1. The role of the fumarate:NADH oxidoreduction in the anaerobic glycolysis of the sea mussel is examined and discussed.
- 2.2. Fumarate reductase activity is present in submitochondrial particles especially from adductor muscle, digestive gland and mantle.
- 3.3. The pH optimum of the enzyme complex is 7.9; the approx Km's for NADH and fumarate are 4.0 × 10−5 M and 6.3 × 10−5 M, respectively.
- 4.4. The enzyme complex is inhibitied by amytal, antimycin, ethanol, malonate, phosphate, rotenone, and succinate, and stimulated by Mg2+.
- 5.5. It is concluded that part of the mitochondrial respiratory chain is involved in the reduction of fumarate by NADH, comprising site 1 of the oxidative phosphorylation.
20.
《The International journal of biochemistry》1976,7(12):647-653
- 1.1. Two cyclic nucleotide-dependent protein kinases have been isolated from chick kidney cytosol on DEAE cellulose.
- 2.2. Both have an apparent Km ATP of 5 × 10−6 M, are stimulated half maximally by 1.8 × 10−8 M cyclic AMP, are inhibited half maximally by 5 × 10−3 M inorganic phosphate, and are inhibited slightly by Tris and chloride ions.
- 3.3. The heat-stable modulator of protein kinase inhibited both activities in the presence of cyclic AMP or cyclic GMP and histone, or cyclic AMP and casein, but with cyclic GMP and casein one kinase was stimulated and the other inhibited.