Beta-endorphin-like and adrenocorticotropin-like materials in turtle heart and intestine

1. Turtle heart and intestine acetone powders were extracted with an acetone-water-HCl mixture. An acid acetone powder resulted by adding a copious volume of acetone to the extract. The powder was subjected to gel filtration on Sephadex G-25 and ion exchange chromatography on CM-cellulose. 2. In turtle heart, corticotropin-like bioactivity was distributed among chromatographic fractions (derived from material unretarded on Sephadex G-25) unadsorbed and adsorbed on CM-cellulose. The highest opiate receptor binding activity and beta-endorphin-like immunoreactivity were adsorbed on CM-cellulose. 3. In turtle intestine, corticotropin-like bioactivity was absent. Opiate receptor binding activity was present in fractions unretarded as well as in fractions retarded on Sephadex G-25, indicating a molecular weight of greater and smaller than 5000 respectively. 4. The highest opiate receptor binding activity and beta-endorphin-like immunoreactivity were found in a fraction adsorbed on CM-cellulose.     

Corticotropin-like material in pigeon brains

1. Pigeon brain acetone powder was extracted with a mixture of acetone, water and hydrochloric acid (40:21:1 v/v/v). The extract was added to a large volume of chilled acetone. 2. The resultant precipitate was washed with cold acetone and then chromatographed on Sephadex G-25. The void volume peak constituted fraction A. The trailing peak immediately following fraction A was divided into two fractions designated B and C. 3. Fraction B (mol. wt less than 5,000) stimulated corticosterone production in isolated rat adrenal cells while the other fractions were devoid of similar ACTH-like bioactivity. 4. None of the fractions showed activity in the opiate radioreceptor assay or hot plate test, implying the absence or presence of only trace amounts of opiate-like materials. Other possibilities that cannot be ruled out include the presence of molecules with substitutions in the sequence by amino acids that result in little or no activity.     

Materials with opiate receptor binding activity in bovine testis and ovine pancreas

Two groups of opiate-like materials, one with a molecular weight equal to or greater than 5000 daltons and another with a molecular weight smaller than 5000 daltons as judged by gel filtration on Sephadex G-25, were detected in bovine testes. The existence of opiate-like materials with a molecular weight smaller than 5000 daltons was demonstrated in ovine pancreas. The pancreatic fraction most strongly adsorbed on CM-cellulose possessed the highest opiate receptor binding activity. Bovine testis contained corticotropin-like material(s) which stimulated corticosterone production by isolated rat adrenal cells.     

Beta-endorphin-like and adrenocorticotropin-like materials in heart tissues of the rat, gerbil, hamster and guinea pig

1. Heart tissues of several rodent species including the rat, gerbil (Meriones unguiculatus), hamster (Mesocricetus auratus) and guinea pig (Cavia porcellus) were extracted with an acetone-water-HCl mixture. An acid acetone powder was obtained by adding a copious volume of acetone to the extract. 2. Rat heart acid acetone powder was subjected to ion exchange chromatography on CM-cellulose. Gerbil heart acid acetone powder was subjected to salt fractionation, gel filtration on Sephadex G-10 and then ion exchange chromatography on CM-cellulose. Hamster and guinea pig heart acid acetone powders were subjected to gel filtration on Sephadex G-25. 3. The fractions were assayed for the ability to stimulate corticosterone production in isolated rat adrenal decapsular (zona fasciculata, zona reticularis and medulla) cells, to displace D-ala2-D-leu5-(tyrosyl-3,5-3H) enkephalin from binding to rat brain membranes, and to inhibit 125I-human beta-endorphin from binding to its antibodies. 4. The widespread occurrence of beta-endorphin-like immunoreactivity among the rat heart CM-cellulose fractions may reflect different species of beta-endorphin. The fraction with the highest beta-endorphin-like immunoreactivity and opiate receptor binding activity was strongly adsorbed on CM-cellulose. 5. In hamster and guinea pig hearts, beta-endorphin-like immunoreactivity and opiate receptor binding activity were distributed among high molecular weight and low molecular weight fractions. 6. In gerbil hearts, opiate receptor binding activity was present in fractions unretarded on Sephadex G-10 (i.e. with a molecular weight greater than 700) as well as in the retarded fractions (i.e. with a molecular weight smaller than 700).(ABSTRACT TRUNCATED AT 250 WORDS)     

Isolation and characterization of calcitonin from pericardium and esophagus of eel.

Calcitonin was extracted from the pericardium and esophagus of eel in quantities sufficient to permit purification and chemical characterization. Homogeneous calcitonin could be isolated by a six-step fractionation starting from acetone powder of the organs. The fractionation procedure consisted of acid extraction, gel filtration on Sephadex G-75, chromatography on SP-Sephadex C-25, gel filtration on the Sephadex G-50, chromatography on carboxymethylcellulose, and gel filtration on Sephadex G-50. Fractionation of the hormone was monitored by assay of its biological activity and from its behaviour on thin layer chromatography and polyacrylamide gel disc electrophoresis. The hormone contained 32 amino acid residues, like calcitonins from other species of animals, but its amino acid composition was different from those of previously characterized hormones. Eel calcitonin possessed almost the same, or higher, biological activity as the salmon or chicken hormone, which show the highest specific activity among calcitonins so far isolated.     

Hormones with adrenocorticotropic and opiate-like activities from the carp (Cyprinus carpio) pituitary

Carp (Cyprinus carpio) pituitary acetone powder was extracted with a mixture of water, hydrochloric acid and acetone. An acid acetone powder was formed by adding the pituitary extract into a large volume of chilled acetone and subsequently recovering the precipitate. The powder was subjected to ion exchange chromatography on CM cellulose. Fractions adsorbed on the ion exchanger exhibited ACTH-like activity as evidenced in the ability to stimulate lipolysis in isolated hamster adipocytes and corticosterone production in isolated rat adrenal decapsular cells and also in cross-reactivity in an ACTH-specific radioimmunoassay. A portion of the ACTH-like bioactivity and immunoactivity was unadsorbed on the ion exchanger. Opiate-like activity in opiate receptor binding assay, employing [3H]D-ala2-D-leu5 enkephalin or [3H]naloxone as ligand, also resided in fractions adsorbed on CM cellulose. The data indicate a separation of ACTH-like and opiate-like activities, and the presence of opiate-like molecules with different affinities of binding to mu and delta opiate receptors.     

Adrenocorticotropin- and beta-endorphin-like substances in brains of the freshwater snake Ptyas mucosa

Snake (Ptyas mucosa) brains (400 g) were extracted with a mixture of acetone, water, and hydrochloric acid. The precipitate (5.6 g) that formed upon addition of five volumes of acetone to the extract, designated acid-acetone powder, was subjected to gel filtration on Sephadex G-25. A large unretarded peak (SB-1) with molecular weight greater than 5000 and a small retarded peak (SB-2) with molecular weight smaller than 5000 were obtained. They were then separately subjected to ion-exchange chromatography on CM-cellulose. Adrenocorticotropic activity was detected in the fractions by their ability to stimulate isolated rat adrenal cells to produce corticosterone. Opiate activity was detected in the fractions by their ability to inhibit the binding of (D-Ala2,D-Leu5)-[tyrosyl-3,5-3H]enkephalin to rat brain membranes and their cross-reactivity in a beta-endorphin radioimmunoassay. Adrenocorticotropic and opiate activities were found to be concentrated in fractions strongly adsorbed on CM-cellulose, which were eluted by combined pH and ammonium acetate concentration gradients. There appeared to be a separation between adrenocorticotropic and opiate activities, suggesting that they were due to separate molecular entities.     

Substances with alpha-melanotropin-like immunoreactivity in bovine brains.

1. Bovine cerebral hemispheres were extracted with an acidic medium (acetone-water-hydrochloric acid mixture, 40:5:1 by volume, pH 1.8). The precipitate which formed upon addition of a copious volume of cold acetone to the extract was designated acid acetone powder (AAP). 2. The AAP was then subjected to ion exchange chromatography on carboxymethyl (CM)-cellulose, gel filtration on Sephadex G100 and Sephadex G25, second ion exchange chromatography on CM-cellulose and high performance liquid chromatography. The absorbance of all fractions was measured at 280 nm and their alpha-melanotropin-(alpha-MSH)-like immunoreactivity was monitored with radioimmunoassay. 3. It was found that alpha-MSH-like immunoreactivity and bioactivity (lipolytic activity) was due to low molecular weight materials as evidenced by their retardation on Sephadex G-100 and Sephadex G-25. The immunoreactivity was distributed among fractions adsorbed and fractions unadsorbed on CM-cellulose and also among high performance liquid chromatographic fractions signifying the presence of multiple alpha-MSH-like molecules.     

Interactions of gold with cytosolic selenium-containing proteins in rat kidney and liver

Rats injected with aurothioglucose (ATG) for 5 days were subsequently injected with [75Se]selenious acid and killed after 3 days. Kidney and liver cytosols were chromatographed on Sephadex G-150. 75Se in kidney was associated with high molecular weight (HMW), 85,000 Mr, 26,000 Mr, and 10,000 Mr proteins and with a nonprotein fraction. The elution profile of liver cytosol was similar to that of kidney, but without a 26,000 Mr protein. ATG injection increased the association of 75Se with all fractions of kidney cytosol except the 85,000 Mr fractions, which contained Se-glutathione peroxidase (SeGSHPx) activity; 75Se in liver was increased only in HMW fractions. Unfractionated kidney cytosolic SeGSHPx activity was decreased 14% by ATG injection, but liver enzyme activity was not changed. However, Sephadex G-150 chromatography showed that total and specific activities, respectively, were decreased 28 and 23% in kidney and 25 and 16% in liver. Au coeluted with HMW and 10,000 Mr 73Se-containing kidney proteins; the latter contained 50% of the Au eluted from the column. DEAE Sephacel chromatography of the 10,000 Mr kidney protein showed that both Au and 75Se were tightly associated with metallothionein-like proteins. This study demonstrates the interaction of Au with rat liver and kidney 75Se-containing proteins.     

Isolation and some observations of the properties of a bovine neurohypophysial milk-ejecting factor.

A substance possessing milk-ejecting activity has been isolated from an acetone powder preparation of bovine posterior pituitary glands by Sephadex G-25 chromatography of the neurophysin-neurohypophysial hormone complex. While the material possessed an oxytocic activity of 2.8 IU/mg as measured on the isolated rat uterus, the milk-ejecting activity was more than three fold greater, 9.6 IU/mg. The peptide had an antidiuretic activity of 0.133 IU/mg and a pressor activity of 0.083 IU/mg. Neither the uterine-stimulating action nor the pressor activity was destroyed by incubating the peptide with 0.01 M sodium thioglycollate at 65 degrees C for 5 min. The oxytocic activity was antagonized neither by 1.4 X 10(-6) M atropine nor 3.3 X 10(-7) M phenoxybenzamine.     

On the nature of the activating enzyme of the inactive form of delta-aminolevulinate synthetase in Rhodopseudomonas spheroides.

The activating enzyme of the inactive form of Fraction I of delta-aminolevulinate (ALA) synthetase [EC 2.3.1.37] in Rhodopseudomonas (R.) spheroides was purified about 1,000-fold from an extract of R. spheroides cells grown anaerobically in the light. The purification of the activating enzyme was achieved by fractionating the 100,000 X g supernatant fraction of the crude extract with ammonium sulfate and acetone, followed by Sephadex G-200 chromatography, pyridoxamine phosphate-Sepharose 4B chromatography, and preparative gel electrophoresis. The final preparation of the activating enzyme still contained a minor contaminant (less than 20%) as judged by disc gel electrophoresis. The activating enzyme exhibited cystathionase [EC 4.4.1.1] activity throughout the purification. These two enzyme activities were not separated at all during any step of the purification. An apparently homogeneous preparation of cystathionase [EC 4.4.1.8] purified from rat liver also exhibited activating activity in the presence of L-cystine. It was concluded that the activating enzyme is a cystathionase.     

The eel pancreas contains opiate-like but not corticotropin-like materials

Eel pancreatic acetone powder was extracted with an acetone-water-HCL mixture. An acid acetone powder was formed by addition of a copious volume of cold acetone to the extract. The powder was subsequently subjected to gel filtration on Sephadex G25. Opiate receptor binding activity was present mainly in fractions retarded on Sephadex G25 (MW less than 5,000) although some activity was present in the unretarded fraction (MW greater than 5,000). Steroidogenic activity was absent from all fractions.     

Production, purification, and characterization of an extracellular chitosanase from Streptomyces.

The synthesis by Streptomyces sp. no. 6 of an extracellular chitosanase was induced by glucosamine. The enzyme was purified to homogeneity by Sephadex G-100, carboxymethyl-cellulose, and diethylaminoethyl-cellulose chromatography. The purified enzyme hydrolyzed chitosan (the beta-1,4-linked polymer of glucosamine) but not chitin nor carboxymethyl-cellulose. The only products of the hydrolysis detectable by paper chromatography were di- and triglucosamine. Sephadex G-100 chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the molecular weight of the enzyme was between 29,000 and 26,000. Acid hydrolysates of the enzyme contained no cysteic acid or glucosamine or other carbohydrate. At 25 C, maximum activity was obtained between pH 4.5 and 6.5. The enzymatic hydrolysis of chitosan occurred over a wide range of temperatures and was maximal at 60 C. The rate of the reaction was inhibited by concentrations of soluble chitosan higher than 0.5 g/liter. The apparent Km calculated from a Lineweaver-Burke plot was 0.688 g/liter at pH 5.5. The enzyme prevented spore germination and caused a significant decrease in the turbidity of germinated spore suspensions of the Mucor strains tested. Such a decrease was the result of a partial lysis of the cell wall.     

Purification of cat submaxillary kallikrein.

The cat submaxillary gland contains 1,000--2,400 kallikrein units (KU)/g of tissue. The submaxillary kallikrein was purified to homogeneity by acetone fractionation, DEAE-Sephadex A-50 chromatography, Sephadex G-75 gel filtration, and Ampholine isoelectric focusing. The kallikrein was separated by isoelectric focusing into 6--7 forms with pI's between 4.2 and 5.1. One mg of the purified kallikrein contained 930--1,260 KU in the dog vasodilator assay, and hydrolyzed 15--25 and 9--12 mumol of N-alpha-benzoyl-L-arginine ethyl ester (BAEE) and N-alpha-toluenesulfonyl-L-arginine methyl ester (TAME), respectively, in 1 min at 25 degrees C and pH 8.0. The Km's of the purified kallikrein with BAEE and TAME were 0.67 and 0.34 mM, respectively. Hydrolysis of N-alpha-benzoyl-L-tyrosine ethyl ester (BTEE), N-alpha-benzoylarginine-p-nitroanilide (BApNA), and casein was small or negligible. The apparent molecular weight of the kallikrein was estimated to be 5 X 10(4) by Sephadex G-100 gel filtration and 4.7 X 10(4) by polyacrylamide gel electrophoresis with sodium dodecyl sulfate (SDS). The kallikrein was found to contain 18.5% carbohydrate by weight. Trasylol and soybean trypsin inhibitor were not specific inhibitors of this kallikrein.     

Identification and characterization of arginine vasopressin-like substances in the rat testis

We have previously demonstrated the suppression of Leydig cell steroidogenesis by arginine vasopressin (AVP) in vitro. Since the circulating level of AVP is too low to mediate a testicular action of this peptide, we have conducted studies to identify testicular AVP-like substances. The supernatant of homogenized, acid-extracted rat testes was found to contain AVP immunoreactivity which showed parallelism with synthetic AVP in a specific radioimmunoassay for AVP. Chromatography of this extract on a Sephadex G-25 column produced three peaks of AVP immunoreactivity. The largest peak eluted close to the column void volume, a second smaller peak eluted at the total column volume, while a third peak co-eluted with synthetic AVP. Following acetone precipitation, ether extraction, and octadecylsilica (C18) adsorption chromatography of the acid extract, the third peak of AVP immunoreactivity (about 600 pg/testis) was fully retained by C18 chromatography and showed parallelism with synthetic AVP in both radioimmuno- and radioreceptor assays. This substance also co-migrated with synthetic AVP on both Sephadex G-25 and reverse-phase thin layer chromatography (RPTLC). The second peak was only partially retained by C18 adsorption chromatography, dilution curves were not parallel with synthetic AVP in radioimmuno- or radioreceptor assay, and this material failed to co-migrate with synthetic AVP on Sephadex G-25 and RPTLC. The first peak of apparent AVP immunoreactivity was associated with an enzyme(s) that degraded labeled AVP. This enzymatic activity, as well as the immunoreactivity, could be eliminated by heating the extract to 90 degrees C. These results demonstrate, by a number of independent criteria, that rat testes contain a substance which behaves like authentic AVP. Due to its high concentration, the AVP-like peptide may be synthesized or concentrated by testis cells. In addition, testis tissue contains enzymatic activity which degrades AVP and could represent a site of regulation of AVP action. Coupled with the previously demonstrated testis action of AVP, these results suggest a paracrine or autocrine role of the neurohypophysial hormone at the testis level.     

Studies on the isolation and chemical properties of porcine follicle-stimulating hormone.

Porcine follicle-stimulating hormone (pFSH) has been prepared from acetone dried pituitary glands. The acetone powder was initially extracted in pH 5 ethanol-acetate buffer (40% ethanol and acetate at 0.5 ionic strength) containing 0.02% PMSF. The gonadotropin rich fraction, obtained in the 80% ethanol precipitate, was dissolved in 0.12 M NH4HCO3, heated at 60 degrees for 3 min, cooled, and centrifuged. The supernatant was lyophilized for chromatography on QAE-Sephadex, then Sephadex G-100. The pFSH obtained has a biological activity of 15 X NIH-FSH-P-1 and 2.1% sialic acid. The amino acid analysis is characterized by high lysine, aspartic acid, and glutamic acid with notable amounts of threonine, proline, and half-cystine.     

Suppressor cell activity in tumor-bearing mice. III. Co-purification of a factor inhibiting cellular DNA synthesis and DNA polymerase activity

The factor(s) derived from fibrosarcoma-induced suppressor T cells was sensitive to pronase and neuraminidase, but not to trypsin, beta-galactosidase, DNase, or RNase. Protein and RNA, but not DNA, synthesis were required to mediate suppression. Suppressor T cell-derived factor(s) could be precipitated by a 50% saturated ammonium sulfate (SAS) solution. The 50% SAS fraction inhibited both in vitro and in vivo spleen cell blastogenesis, whereas the 80% and unprecipitated fractions had no inhibitory activity. Using Sephadex G-200 chromatography, the 2nd protein fraction (fraction II) contained an inhibitor of both DNA polymerases (IDP) and DNA synthesis (IDS) activity, which possessed no cytotoxic activity. In vitro DNA polymerase alpha activity was suppressed by fraction II, whereas DNA polymerase beta and gamma activities remained unchanged. Molecular weight of IDP/IDS, as determined by Sephadex G-200 gel filtration chromatography, was approximately 14,500. Attempts to separate IDP/IDS activities found in fraction II by anion-exchange chromatography and slab gel electrophoresis were not successful, which suggested that the 2 activities were the same or very similar molecules.     

Rat-liver lysosomal sialidase. Solubilization, substrate specificity and comparison with the cytosolic sialidase

Purified liver lysosomes, prepared from rats previously injected with Triton WR-1339, exhibited sialidase activity towards sialyllactose, fetuin, submaxillary mucin (bovine) and gangliosides, and could be disrupted hypotonically with little loss in these activities. After centrifugation, the activities with sialyllactose and fetuin were largely recovered in the supernatant, demonstrating that they were originally in the intralysosomal space. The activities towards submaxillary mucin and gangliosides, on the other hand, remained in the pellet. In the supernatant, activity with fetuin or orosomucoid was markedly reduced by protease inhibitors, suggesting that proteolysis of these glycoproteins may be prerequisite to sialidase activity. The intralysosomal sialidase was solubilized from the mitochondrial-lysosomal fraction of rat liver and partially purified by Sephadex G-200, or Sephadex G-200 followed by CM-cellulose. The enzyme was maximally active at pH 4.7 with sialyllactose as substrate and had a minimum relative molecular mass of 60 000 +/- 5000 by gel filtration; it hydrolyzed a variety of sialooligosaccharides , those containing (alpha 2----3)sialyl linkages being better substrates than those with (alpha 2----6)sialyl linkages. The enzyme failed to attack submaxillary mucin and gangliosides. It was also inactive towards fetuin, orosomucoid and transferrin but capable of hydrolyzing glycopeptides from pronase digest of fetuin. In contrast to the intralysosomal sialidase, the sialidase partially purified from rat liver cytosol by (NH4)2SO4 fractionation followed by chromatography on DEAE-cellulose and CM-cellulose hydrolyzed fetuin and orosomucoid to the extent about half that for sialyllactose. The enzyme was maximally active at pH 5.8 and had a relative molecular mass of approximately 60 000. It also hydrolyzed gangliosides but not submaxillary mucin.     

Isolation and fractionation of glycopeptides from porcine thyroglobulin

1. Glycopeptides were isolated by gel filtration on Sephadex G-25 and Sephadex G-50 from a Pronase digest of porcine thyroglobulin. 2. Isolated glycopeptides were separated into five main fractions on a column of DEAE-Sephadex A-25. Of these fractions I to III were further purified by SE-Sephadex C-25 or DEAE-Sephadex A-25 column chromatography. Several of the purified glycopeptides were homogeneous on paper electrophoresis. 3. Based on the chemical composition and molecular weight of the fractionated glycopeptides, two distinct types of heterosaccharide chain were demonstrated. 4. One type of the heterosaccharide unit consisted of four to eight residues of mannose and two residues of glucosamine and had a molecular weight of 1000-1700. The other type of unit contained sialic acid, fucose and galactose in addition to mannose and glucosamine and had a molecular weight of about 3600. 5. Mild alkaline treatment of the glycopeptide did not result in the destruction of threonine and serine. 2-Acetamido-1-N-(4-l-aspartyl)-2-deoxy-beta-d-glucopyranosylamine was isolated from partial acid hydrolysates.     

猪垂体Beta-脂肪酸释放激素(β-LPH)化学修饰及活性研究

本文以自行制备的βP-LPH为原料,用焦碳酸二乙酯(DEPC)为修饰剂,对βP-LPH分子中的组氨酸进行化学修饰,井对修饰前、后的βp-LPH进行CD光谱测定、脂肪酸释放活性及免疫学活性测定。结果表明:修饰后的βP-LPH脂肪酸释放活性部分下降,而免疫学活性几乎完全丧失。