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1.
Isolation of ACTH1-39,ACTH1-38 and CLIP from the calf anterior pituitary   总被引:2,自引:0,他引:2  
Calf anterior pituitaries were defatted and homogenized and peptides were adsorbed from the homogenate supernatant onto octadecylsilyl-silica. After elution, the resulting extract was subjected to gradient elution reversed-phase high pressure liquid chromatography (RP-HPLC) using aqueous acetonitrile containing 0.1% (vv) trifluoroacetic acid (TFA). Radioimmunoassay of column fractions for corticotropin (ACTH) revealed three major areas of immunoreactivity. Each was purified to homogeneity by gradient elution RP-HPLC employing aqueous acetonitrile containing either 0.13% heptafluorobutyric acid (vv) or 0.1% TFA (vv). Amino acid analysis and exopeptidase and trypsin digestions revealed the three forms of corticotropin to be ACTH1–38, corticotropin-like intermediary lobe peptide, (CLIP, ACTH18–39) and ACTH1–39. 3H-labeled ACTH1–39 did not give rise to either 3H-ACTH1–38 or 3H-CLIP during isolation.  相似文献   

2.
The cross-reactivities of the big and small forms of prothoracicotropic hormone (PTTH) from pupal brains of Manduca sexta and egg-development neurosecretory hormone (EDNH) from heads of adult Aedes aegypti were examined for PTTH by the in vitro Manduca prothoracic gland assay and for EDNH by the in vitro and in vivo Aedes ovary assays. The synthesis of ecdysone by both larval and pupal prothoracic glands of Manduca was increased in a dose-dependent manner by crude extracts of Aedes aegypti heads, reaching a maximum of approx. 3- and 2-fold, respectively. Gel filtration chromatography of the Aedes head extract revealed a peak of EDNH activity with an apparent mol. wt of 11 kD. This partially purified EDNH did not possess prothoracicotropic activity in the in vitro prothoracic gland assay, nor did any other fractions from the gel filtration column. Similarly, partially purified big and small PTTH did not activate Aedes atropalpus ovaries to synthesize ecdysone in vitro, nor did they cause ovarian maturation in vivo. Thus, it appears that the structural differences between PTTH and EDNH are sufficient enough to prevent functional cross-reactivity. The apparent discrepancy in the results obtained with the crude and partially purified EDNH and PTTHs raises questions about the reliability of bioassays for screening the presence and cross-reactivity of peptide neurohormones in crude extracts.  相似文献   

3.
The molecular weight distribution of sinistrin (Inutest ®, Laevosan Ges., Linz, Austria), determined by analytical gel-permeation chromatography, using narrow fractions (MwMn< 1.07) obtained by preparative gel-permeation chromatography, covered the range 800–16,000 with Mn  2,500 and Mw  3,500. From viscosity measurements on dilute, aqueous solutions, the relation [η]  0.28 X M0.3 was obtained, indicating a branched molecular structure; the largest molecules can be described by a sphere with r  23 Å. Comparison of the content of glucose and reducing sugars in the fractions with the molecular weight determined by vapour-pressure osmometry indicated that a glucose end-group is present in the majority of the molecules. The percentage of glucose end-groups is higher in the fractions of lower molecular weight. From this finding, speculations on the biosynthesis of sinistrin are made. The specific optical rotation of sinistrin fractions decreases linearly with 1/Mn.  相似文献   

4.
Timothy G. Kingan 《Life sciences》1981,28(23):2585-2594
Standard biochemical procedures were used to purify the prothoracicotropic hormone (PTTH) 4400 fold from whole head extracts of Mandurasexta fifth instar larvae. Hormonal activity was bioassayed by injection into neck-ligated fourth instar larvae. The hormone was stable to heating at 85°C. Ammonium sulfate and acetone fractionation provided a crude preparation which showed dose-dependent activity in the bioassay. Chromatography on Sephadex G-100, DEAE-Sephadex, and hydroxylapatite gave a preparation with 2.6 Manduca PTTH units/μg protein (4400-fold purification). Activity was sensitive to proteolytic enzymes. Further purification by preparative electrophoresis gave a preparation which migrated as a single band in two polyacrylamide gel electrophoresis systems. A molecular weight estimate of 25,000 Daltons was obtained for this bands on SDS polyacrylamide gels.  相似文献   

5.
Considerable disagreement exists between results reported by various authors for lipid composition and enzyme activity in purified muscle membrane fractions presumed to be sarcolemma, although an explanation for these discrepancies has not been presented. We have prepared muscle light surface membrane fractions of comparable density (1.050–1.120) by a low-salt sucrose method and by an LiBr-KCl extraction procedure and compared them for density profile, total lipid and cholesterol content, protein composition and ATPase activity. In addition, sodium channels characteristic of excitable membranes have been quantitated in each preparation using [3H]saxitoxin binding assays, and the density of acetylcholine receptors determined in fractions from control and denervated muscle using α-[125I]bungarotoxin. Although both fractions contain predominantly surface membrane, the LiBr fraction consistently shows the higher specific activity of p-nitrophenylphosphatase, higher free cholesterol content, and higher density of sodium channels and acetylcholine receptors. The density distribution of sodium channels appears uniform throughout both fractions. Quantitative differences were seen between sodium dodecyl sulfatepolyacrylamide gel electrophoresis patterns of membrane proteins from the two preparations although most bands are represented in both. A majority of the low-salt sucrose light membrane proteins were accessible in varying degrees to labelling with diazotized diiodosulfanylic acid in intact muscle. These results suggest that light surface membrane fractions may be mixtures of sarcolemma and T-tubular membranes. Using our preparative methods, the LiBr fraction may contain predominantly sarcolemma while low-salt sucrose light membranes may be enriched in T-tubular elements.  相似文献   

6.
Activity of a penicillin-insensitive DD-endopeptidase that splits the D-alanyl-meso-2,6-diaminopimelyl linkage in peptidoglycan was demonstrated in a sonic extract of Escherichia coli. The protein with this activity was partially purified. The activity was inhibited by 3 μg per ml of deoxyribonucleic acid, suggesting that this cell wall hydrolytic enzyme is regulated by deoxyribonucleic acid or its fragments.  相似文献   

7.
Egg development neurosecretory hormone (EDNH), a hormone that stimulates vitellogenesis in mosquitoes, was purified 10,000-fold from the mosquito Aedes aegypti. The purification procedure included chromatography on hydrophobic, ion exchange, and gel filtration columns, and preparative electrophoresis to give an almost homogeneous preparation. The hormone is a polypeptide monomer of molecular weight of 18,700 ± 500 as determined from SDS electrophoresis and gel filtration chromatography. Using lowpressure chromatography throughout the purification procedure, the hormone was recovered at a high yield (39%). The amount of EDNH in a mosquito is about 0.6-1.6 ng, corresponding to 32–85 fmol. Injection of purified EDNH into female mosquitoes resulted in the conversion of [14C]cholesterol into labeled ecdysone and 20-hydroxyecdysone which were separated and identified using thin-layer chromatography and high-performance liquid chromatography separation procedures. Egg development and vitellogenin synthesis were also induced when EDNH was injected into several mosquito species, indicating that the hormone is not species-specific. This report is the first to show that a purified preparation of EDNH has both steroidogenic and a gonadotropic effects on female mosquitoes.  相似文献   

8.
β-Glucuronidase activity was measured in mouse embryos during the preimplantation period of development by using a microfluorometric assay. A 100-fold increase in activity was observed between 57 (8-cell stage) and 84 hr (morulae) of development. Activity changes between 30 and 60 hr were also significant. Genetic variants of β-glucuronidase occur between the strains of mice C57BL6J and C3HHeJ which differ in levels of activity and heat denaturation kinetics. Activity changes and heat denaturation kinetics of β-glucuronidase in C57BL6, C3HHeJ and F1 hybrid embryos were compared, and it was demonstrated that paternal genes were expressed during the 100-fold increase in activity and that embryonic genes may be functioning between 30 and 60 hr of development.  相似文献   

9.
Three forms of endo-(1→3)-β-g-glucanases lysing yeast cell walls from Rhizoctonia solani were separated by precipitation with ammonium sulfate and by successive chromatographies on CM Bio-Gel A and Bio-Gel P-60 or P-30, and were finally purified by substrate affinity chromatography on short-chain pachyman-AH-Sepharose CL 6B column. Each preparation was found to be homogeneous on gel filtration and by electrophoresis on acrylamide gel with sodium dodecyl sulfate. They exhibit high activity against insoluble pachyman, but only restricted activity against soluble short-chain pachyman. In the affinity chromatography, three enzymes were found to be strongly absorbed on the column, so that they could be easily eluted with substrate solution using biospecific counter-ligand. It was thus revealed that covalent binding of such a soluble glucan to aminohexyl-Sepharose provides a useful carrier for separation of endo-(1→3)-β-D-glucanases lysing yeast cell walls.  相似文献   

10.
T4 bacteriophage mRNA for lysozyme was extracted from T4 phage infected E. coli cells, partially purified by column chromatography, and translated in a heterologous cell-free protein synthesizing system prepared from wheat germ. The translation product was confirmed by SDS polyacrylamide gel electrophoresis and enzymatic activity — bacteriolysis as tested with Micrococcus luteus. The specific activity of the enzyme prepared was 660 U/mg.  相似文献   

11.
Purification of starch branching enzymes from kernels of two nonlinked mutants of maize, sugary and amylose-extender, showed the basis of the two mutations to be associated with branching enzymes I and IIb, respectively. Branching enzyme I from sugary kernels purified as nonmutant branching enzyme I, but had an altered pattern of activity when amylose was used as a substrate. In addition to the typical fall in absorbance at high wavelengths (550–700 nm) of the amylose-iodine complex, branching of amylose by sugary branching enzyme I caused an increase in absorbance at low wavelengths (400–550 nm). Branching enzyme IIb was undetected in extracts of amylose-extender kernels, while branching enzymes I and IIa appeared unaltered. Low umprimed starch synthase activity was also observed in DEAE-cellulose fractions of amylose-extender maize, but this activity was regenerated by the addition of any branching enzyme.  相似文献   

12.
A low-molecular-weight interferon-mediated ribosome-associated inhibitor of reovirus mRNA translation was purified from the 0.5 M KCl ribosomal salt-wash fraction of mouse L929 cells. The inhibitor possessed nucleolytic activity with reovirus [3H]mRNA as a substrate. Loss of translational inhibitory activity correlated with the thermal inactivation of the nuclease. A low-molecular-weight (<10K) component present in the Bio-Gel P150 chromatography fractions which contained the interferon-mediated nucleolytic activity was labeled in vivo with [14C]valine; a smaller component present in the same fractions was phosphorylated in vitro with [γ-32P]ATP. The <10K components were resolved from ~50K, ~30K and ~20K phosphorylatable proteins associated with ribosomes that possess the interferon-mediated inhibitor(s) of viral mRNA translation.  相似文献   

13.
Cytochrome P-450 was purified to a content of over 17 nmoles per mg of protein from liver microsomes of phenobarbital-treated rabbits by fractionation with polyethylene glycol 6000, DEAE-cellulose column chromatography, and hydroxylapatite column chromatography in the presence of Renex 690, a nonionic detergent. The purified preparation exhibited a single polypeptide band (molecular weight, 49,000 daltons) when submitted to SDS-polyacrylamide gel electrophoresis. Cytochromes P-420 and b5 and NADPH-cytochrome c reductase were absent. The reconstituted system containing purified cytochrome P-450, reductase, and phosphatidylcholine catalyzed the hydroxylation of benzphetamine, cyclohexane, aniline, and laurate.  相似文献   

14.
Two fractions with prostaglandin E-like activity were isolated from onion (Allium cepa) by using XAD-2 adsorption, silicic acid column chromatography and thin layer chromatography. The fractions were analyzed by gas chromatography/mass spectrometry and were characterized as isomeric mixtures of 9,10,13-trihydroxy-11-octadecenoic and 9,12,13-trihydroxy-10-octadecenoic acid, which are lipoxygenase metabolites of linoleic acid. Bio-assay, for which cascade superfusion was used and the rabbit coeliac and mesenteric arteries and the rat fundus strip were employed as assay organs, was utilized to monitor the bio-active profile throughout the isolation procedures. The activity of 1 μg of the pharmacologically active fractions T1 and T2 was found to be equivalent to that of respectively 1.33 and 0.63 ng of prostaglandin E2.  相似文献   

15.
A soluble Ad2 DNA synthesizing complex was prepared from Ad2-infected KB cell nuclei and purified by exclusion chromatography on a BioGel A-50m column. The purified complex was able to synthesize DNA from all regions of the virus genome, as indicated by EcoRI restriction endonuclease analysis of in vitro labeled DNA. Experiments were performed to identify Ad2-induced early polypeptides present in the complex. Ad2-infected and mock-infected cells were labeled with [35S]methionine 7–10 h postinfection, then incubated for 8 h to allow the 35S-labeled early polypeptides to become associated with the complex. The polypeptides in the purified complex and each of the cell fractions were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography. The major components of the purified complex were the 73K DNA binding phosphoprotein and 11K, two adenovirus 2-induced early polypeptides. The 11K has a preferred nuclear location. Small quantities of other Ad2-induced early proteins, 21K, 15K, and possibly 8.3K were also associated with the complex.  相似文献   

16.
Purification of thiamine-binding protein from Escherichia coli   总被引:2,自引:0,他引:2  
An affinity column coupled with thiamine pyrophosphate quantitatively absorbs the thiamine-binding activity from a partially purified preparation of Escherichiacoli. The thiamine-binding protein can be eluted from the affinity column in high yield by use of 8 M urea-containing buffer. Approximately 90-fold purification occurs by affinity chromatography yielding a preparation which appears to be homogenous.  相似文献   

17.
A template independent poly (A)·poly (U) synthesizing activity has been isolated from Bacillus subtilis. This activity is eluted from a DNA-cellulose column along with DNA-dependent RNA polymerase. The column fractions which exhibit this activity contain RNA polymerase holoenzyme plus a polypeptide which is slightly larger than sigma factor; pure RNA polymerase holoenzyme did not synthesize poly (A)·poly (U). The activity was dependent on the presence of ATP, UTP, and Mn++ (Mg++ could not substitute), and was inhibited by rifampicin, streptolydigin, and Cibacron Blue. The incorporation of nucleotides was not linear with time, but appeared after a lag period. The results suggest that a modified form of DNA-dependent RNA polymerase analogous to Escherichia coli holoenzyme II is catalyzing the synthesis of poly (A)·poly (U).  相似文献   

18.
The content of the sigma subunit (as detected by gel electrophoresis) and activity with T4 DNA were examined with RNA polymerase fractions from both normal and T4 phage-infected E. coli. Sigma-containing fractions and core enzymes were obtained by phosphocellulose column chromatography. The sigma-containing fraction of the enzyme from infected cells, although somewhat stimulatory to both core enzymes alone, inhibits the normal sigma-stimulated activity of the core enzyme from infected cells at both low and high KCl concentration. Normal core enzyme activity is inhibited only at high KCl concentration.  相似文献   

19.
Heparin was converted by treatment with nitrous acid primarily into sulfated disaccharides. The mixture of disaccharides was reduced with sodium boro[3H]hydride and the disaccharides were purified by preparative paper electrophoresis and paper chromatography. Four disaccharides were obtained. On the basis of their paper electrophoretic mobilities and the products formed at intermediate stages of their acid hydrolysis, the disaccharides were identified as 4-O-(2-O-sulfo-α-l-idopyranosyluronic acid)-6-O-sulfo-2,5-anhydro-d-mannitol, 4-O-(2-O-sulfo-α-l-idopyranosyluronic acid)-2,5-anhydro-d-mannitol, 4-O-(α-l-idopyranosyluronic acid)-6-O-sulfo-2,5-anhydro-d-mannitol, and 4-O-(β-d-glucopyranosyluronic acid)-6-O-sulfo-2,5-anhydro-d-mannitol. The purified disaccharides were used as standards in the development of a high-performance liquid chromatography procedure for their separation and quantitation on a Partisil-10 SAX anion-exchange column. The three monosulfated disaccharides were resolved by isocratic elution with 40 mm KH2PO4. The KH2PO4 concentration was tehn increased to 400 mm to elute the disulfated disaccharide. Column effluents were collected in 12-ml fractions, and the recovery of each 3H-labeled product was determined by scintillation counting. When sodium boro-[3H]hydride with a specific activity of 315 mCi/mmol was used in the reduction of the heparin deamination products, the disaccharides gave 28,500 cpm/nmol in the effluent peaks. Quantitative recoveries of the 3H-disaccharides were obtained. It was demonstrated that the method developed using the purified disaccharides gave reproducible and quantitative results in direct assays of aliquots of boro[3H]hydride-reduced heparin deamination mixtures.  相似文献   

20.
The somatic extract of mature T. pisiformis has been demonstrated to contain a potent inhibitor capable of inactivating the esterolysis of N-α-benzoyl-L-arginine ethyl ester and N-benzoyl-L-tyrosine ethyl ester by trypsin and chymotrypsin, respectively, of bovine, dog and rabbit origin, but not affecting the caseinolytic activity of subtilisin and elastase. The protease inhibitor, partially purified by trichloroacetic acid treatment, Sephadex G-100 column chromatography and affinity chromatography on CNBr-activated Sepharose 4B-bovine chymotrypsin conjugate, was soluble in 5% trichloroacetic acid, stable to heating at 100°C for up to 30 min, tolerated the pH range of 1.5–9.0, and was unaffected by 8 m-urea or 0.2 M-2-mercaptoethanol. The molecular weight of the inhibitor was estimated to be 7000–7200 by Sephadex G-100 chromatography. Activity determinations on crystalline bovine trypsin and chymotrypsin revealed that both inhibitory actions are located on the same or closely adjacent sites of the inhibitor molecule. Complex formation between the inhibitor and mammalian trypsin and chymotrypsin required 3–4 min for completion.  相似文献   

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