Synthesis of low-phenylalanine polypeptides

Low-phenylalanine-peptides for dietotherapy of phenylketonuria (PKU) were prepared from soybean protein isolate. Soluble fraction of soybean protein isolate was hydrolysed by alpha-chymotrypsin then followed by carboxypeptidase-A. Molecular weight distribution and amino acid analysis were made on the resultant polypeptides. The chymotrypsin hydrolysate was divided into two fractions, Fraction I (molecular weight greater than 2500) and Fraction II (molecular weight between 1000 and 2500). The phenylalanine content of Fraction I (3.1%) was lower than that of Fraction II (5%), indicating the nonuniform distribution of phenylalanine in soy bean protein. Carboxypeptidase hydrolysis of Fraction I further reduced the phenylalanine concentration to 2.3%, approximately half of the original concentration in soybean protein isolate.     

Studies of soluble rat liver mitochondrial acid ATPases: II. Structural and immunological properties of ATPase 1

We described previously the existence of a soluble ATPase activity in rat liver mitochondria [1]. The purification and catalytic properties have been described [2]. In a continuation of these experiments, we have studied the immunologic and structural properties of one molecular form of this enzyme: ATPase I.We have prepared the antiserum anti-ATPase I and demonstrated the purity of our enzyme preparation by immunodiffusion and immunoelectrophoresis. An immunohistochemical method also confirmed the localization of ATPase I in the soluble fraction of mitochondria.The molecular weight of ATPase I was measured by G 100 Sephadex gel filtration and was found to be 18,400; electrophoresis on polyacrylamide gels gave a value of 18,600. The pHi of ATPase I was found to be 7,2.Amino acid analysis showed high amounts of aspartic acid, glutamic acid, serine and glycine. The molecular weight calculated from the total amino acid residues was found to be 17,000.Alanine is the NH2 terminal amino acid.The peptide maps obtained after degrading ATPase I with cyanogen bromide or trypsin are in accordance with the methionine, lysine and arginine residues we found in the ATPase I molecule.ATPase I does not appear to be a glycoprotein.     

Studies of soluble rat liver mitochondrial acid ATPases. II. Structural and immunological properties of ATPase 1.

We described previously the existence of a soluble ATPase activity in rat liver mitochondria [1]. The purification and catalytic properties have been described [2]. In a continuation of these experiments, we have studied the immunologic and structural properties of one molecular form of this enzyme : ATPase I. We have prepared the antiserum anti-ATPase I and demonstrated the purity of our enzyme preparation by immunodiffusion and immunoelectrophoresis. An immunohistochemical method also confirmed the localization of ATPase I in the soluble fraction of mitochondria. The molecular weight of ATPase I was measured by G 100 Sephadex gel filtration and was found to be 18,400; electrophoresis on polyacrylamide gels gave a value of 18,600. The pHi of ATPase I was found to be 7,2. Amino acid analysis showed high amounts of aspartic acid, glutamic acid, serine and glycine. The molecular weight calculated from the total amino acid residues was found to be 17,000. Alanine is the NH2 terminal amino acid. The peptide maps obtained after degrading ATPase I with cyanogen bromide or trypsin are in accordance with the methionine, lysine and arginine residues we found in the ATPase I molecule. ATPase I does not appear to be a glycoprotein.     

Recovery of tryptophan from 25-minute acid hydrolysates of protein

It was found that thioglycolic acid prevents destruction of tryptophan during rapid hydrolysis of protein with a trifluoroacetic acid/HCl mixture (1:2, v/v) at 166 degrees C for 25 or 50 min. The addition of 5% (v/v) thioglycolic acid gave the maximum tryptophan recovery (88.3%) for a 25-min hydrolysate of lysozyme. Tryptophan recoveries varied slightly among three different proteins; 88% for lysozyme, 73% for alpha-chymotrypsinogen A, and 85% for apomyoglobin. However, when extrapolated to zero time, the values were close to one another: 94, 87, and 88%, respectively. The addition of thioglycolic acid was also advantageous for recovering amino acids other than tryptophan. Particularly, yields of carboxymethylcysteine and methionine were greatly improved. This modified rapid hydrolysis method gave satisfactory results without the need for separate analyses of tryptophan and cysteine, provided proteins were reduced and carboxymethylated prior to hydrolysis.     

Purification and identification of [hydroxyprolyl3]bradykinin in ascitic fluid from a patient with gastric cancer

Kinins in the ascitic fluid from a patient with gastric cancer were purified by gel filtration and reversed-phase high-performance liquid chromatography (HPLC). Two fractions (fractions I and II) showed kinin activity. Fraction I did not correspond to either bradykinin or other known kinins, whereas fraction II corresponded to bradykinin. Fraction I contained 8 amino acid residues from bradykinin minus 1 proline plus 1 additional hydroxyproline. Sequence analysis of fraction I showed that the proline at the third amino acid residue of bradykinin was replaced by hydroxyproline. The retention time of fraction I on reversed-phase HPLC was exactly the same as that of synthetic [hydroxyprolyl3]bradykinin (Arg-Pro-Hyp-Gly-Phe-Ser-Pro-Phe-Arg) and was distinguishable from des-Pro3-bradykinin. Thus, these results demonstrate for the first time the presence of [hydroxyprolyl3]bradykinin in vivo. This is also the first report of the presence of bradykinin in human tumor ascites.     

Isolation and Properties of Carbohydrate Rich Fraction of Wheat Gluten

Two carbohydrate rich fractions A and B were isolated from wheat gluten. Fraction B contained more lipid than fraction A. Lipid portion of fraction B consisted mainly of glycolipid and was fractionated into five fractions by thin-layer chromatography. The two main fractions were extracted and determined to be galactolipid and glucolipid, respectively, by the analyses of fatty acid and sugar components by gas chromatography. Defatted fraction A was assumed to consist of glycoprotein. After complete pronase digestion of defatted fraction A, the remaining glycopeptide moiety was isolated by column chromatography on DEAE-cellulose followed by gel filtration through Sephadex G–25. The amino acid and sugar components of the glycopeptide were investigated.     

Molecular Weight Determination of Gliadin Fractions in Gel Filtration by SDS-Polyacrylamide Gel Electrophoresis and Sedimentation Equilibrium

Gliadin was fractionated into three fractions; ω-gliadin, Fraction III (γ-gliadin) and Fraction IV (α- and β-gliadin). The determination of the molecular weights (MW) of the three fractions was performed by both SDS-polyacrylamide gel electrophoresis (SDS–PAGE) and sedimentation equilibrium. In SDS–PAGE, ω-gliadin gave three bands (MW 50,000, 54,000 and 64,000), Fraction III two bands (MW 38,000 and 46,000) and Fraction IV two bands (MW 33,000 and 38,000), The sedimentation analysis showed that each fraction was fairly homogeneous relative to molecular weight. The molecular weights obtained by sedimentation were 28,000 for Fraction III and 27,000 for both Fraction IV and ω-gliadin. The disagreement in molecular weight between sedimentation and gel electrophoresis was discussed.     

Occurrence of 5SrRNA in high molecular weight complexes of aminoacyl-tRNA synthetases in a rat liver supernatant.

The 5SrRNA in the rat liver postmicrosomal supernatant was investigated. Acrylamide gel electrophoresis and Northern blot analysis showed that most of the 5SrRNA was present in the fractions obtained on high molecular weight regions separated by Sephadex G-200 column chromatography of the supernatant, which contained the bulk of the methionyl-tRNA synthetase (Fraction I) and tyrosyl-tRNA synthetase (Fraction II). A high molecular weight complex containing nine aminoacyl-tRNA synthetases [Mirande, M., LeCorre, D., & Waller, J.-P. (1985) Eur. J. Biochem. 147, 281-289] was purified by fractional precipitation with polyethylene glycol 6000, gel filtration on Bio-Gel A-1.5m, and finally tRNA-Sepharose column chromatography, which gave two fractions. Fraction B showed the activities of nine aminoacyl-tRNA synthetases and gave protein bands corresponding to eight previously identified enzymes on SDS-PAGE. Fraction A, eluted with a lower KCl concentration than Fraction B, showed lower activities than fraction B of eight of the aminoacyl-tRNA synthetases, the exception being prolyl-tRNA synthetase. The staining patterns with ethidium bromide of the RNAs after PAGE showed 5SrRNA bands for Fraction A but not for Fraction B. However, Northern blot analysis indicated that 5SrRNA was present in both Fractions A and B. The staining pattern after SDS-PAGE of Fraction A with Coomassie Brilliant Blue showed several protein bands in addition to those observed for Fraction B, one of which, with a staining intensity comparable with those of other bands, was located at the same position as ribosomal protein L5, which is the protein moiety of the 5SrRNA-L5 protein complex of ribosomal 60S subunits.(ABSTRACT TRUNCATED AT 250 WORDS)     

Extraction and purification of tissue phosphopeptides

We describe a method of extraction and partial purification of phosphopeptides isolated from pig brain or from the electrical organ of Torpedo marmorata. The extraction of the phosphopeptides was achieved by alcoholic 0,04 N potassium hydroxyde solution or by 10(-1) M KCL containing 10(-3) M EDTA and 10(-4) M DTT. After having tried various fractionation methods like ion exchange chromatography or gel filtration we chose chromatography on DEAE Sephadex followed by purification of the isolated fractions by Sephadex G 25 filtration. The most important phosphate fractions (one was purified to about 90 per cent) were characterized by the determination of the N/P ratio which was different from one phosphopeptide to another. The amino acid composition showed a high glycin, serine and "acid" amino acid content.The presence of phosphoserine was shown by electrophoresis and chromatography of a partial hydrolysate of in vivo 32P labelled phosphopeptides isolated from rat liver. The polyanionic structure of these phosphopeptides allow them to act as real ion exchangers which might be involved during active transport mechanisms in cellular membranes.     

Isolation and characterization of immunopeptide from dialyzable leukocyte extract

The dialyzable leukocyte extract was fractionated using high-pressure liquid chromatography through an anion exchange column (preparative). Twenty-one fractions were obtained. Fraction 1, which gave maximum enhancement of E rosettes, was further purified by thin-layer chromatography on silica gel plates. Five ninhydrin-positive bands were seen. The area under each band was scraped from the plates and eluted. The fastest moving component was labeled S1 and the slowest moving S5. Fraction S3 had given maximum enhancement of E rosettes and was designated as immunopeptide. The immunopeptide was further characterized. It contained protein, ribose, and hexose. The molecular weight was determined to be 1870 by sedimentation equilibrium method. It contained 15 amino acid residues. The immunopeptide enhanced E-rosette formation in vivo when given in doses of 5 units/m², to four individuals with low E rosettes.     

Inhibition of basal and calmodulin-activated Ca2+-pump ATPase by fractionated compound 48/80

Compound 48/80 (48/80), a mixture of polycationic compounds was fractionated using affinity chromatography on calmodulin-Sepharose. Unfractionated 48/80 and various fractions were tested for their potential inhibitory effects on ATPase activities of isolated human red blood cell membranes. ATPase activities tested included: Mg2+-ATPase, the Na+/K+-pump ATPase, and the Ca2+-pump ATPase in both its basal (calmodulin-independent) and calmodulin-activated state. Neither 48/80 nor its various fractions were very potent or efficacious inhibitors of the Mg2+-ATPase or the Na+/K+-pump ATPase. In agreement with previous reports, 48/80 was found to be an inhibitor of the calmodulin-activated Ca2+-pump ATPase. By contrast, we found that unfractionated, as well as some fractionated, material inhibited both the basal (calmodulin-independent) and calmodulin-activated Ca2+-pump ATPase activity. A fraction designated as Fraction III bound to calmodulin-Sepharose in the presence of Ca2+ and low salt and was eluted in the absence of Ca2+ and 0.15 M NaCl. By gel filtration, Fraction III had an apparent average molecular weight of 2064 (1320 for unfractionated material). Fraction III was the most potent inhibitor of the Ca2+-pump ATPase with IC50 values for the basal and calmodulin-activated forms of the enzyme of 0.6 and 1.2 micrograms/ml, respectively. Inhibition by Fraction III was cooperative with n apparent values of 2.4 and 5.7, respectively, for the basal and calmodulin-activated forms of the enzyme. Thus, binding of 48/80 constituents to calmodulin can not fully account for the observed data. Direct interaction of 48/80 constituent(s) with the enzyme and/or the lipid portion of the membrane is suggested.     

Studies on protein–polysaccharides from pig laryngeal cartilage. Heterogeneity, fractionation and characterization

1. Protein-polysaccharides from pig laryngeal cartilage extracted by two procedures described in the preceding paper (Tsiganos & Muir, 1969) were shown to consist of macromolecules of various sizes as assessed by gel filtration in 4% and 6% agarose. 2. A larger proportion of the smaller molecules was present in the preparation obtained by brief extraction in iso-osmotic sodium acetate (procedure I) than in that obtained by more prolonged extraction in 10% (w/v) calcium chloride (procedure II). 3. Two fractions were separated by gel filtration in 6% agarose and by electrophoresis in compressed glass fibre. These fractions differed in chemical composition and in antigenic determinants. The gel-retarded fraction R and that of higher electrophoretic mobility possessed the same single antigen, whereas the gel-excluded fraction E and the slower electrophoretic fraction contained all the antigens of the starting material including that of fraction R. 4. Five N-terminal amino acid residues were identified in preparation I and fraction E, only two of which were present in fraction R. 5. The relative proportions of gel-excluded and gel-retarded fractions did not change when solutions of high ionic strength, urea or guanidine hydrochloride were used for elution. 6. The differences in chemical and amino acid composition between fractions R and E showed that the latter was not a simple aggregate of the former. Fraction E contained more basic and aromatic amino acids, and some methionine and cystine; the last two were absent from fraction R. Hydroxyproline was not detected in either fraction. 7. The number of glycosidic linkages in both fractions was estimated by alkaline beta-elimination. Appreciable amounts of threonine as well as serine were destroyed in both fractions. An average chain length for chondroitin sulphate was calculated from the galactosamine content of both fractions and the amounts of hydroxy amino acid destroyed. Average chain lengths were also calculated from the xylose and galactosamine content of each fraction. Each independent method gave a value of approximately 28 disaccharide units for the chain length in both fractions and hence their difference in size could not be explained by differences in the length of carbohydrate chains. 8. All fractions contained glucosamine, which was attributed to keratan sulphate. Content of both protein and keratan sulphate increased with the size of the macromolecules. 9. It is suggested, from these results, that chondroitin sulphate-protein complexes normally exist as a heterogeneous population of macromolecules in cartilage, and that keratan sulphate is involved in the formation of larger molecules.     

Studies of dynein from Tetrahymena cilia using agarose polyacrylamide gel electrophoresis.

Described in this report is an application of agarose-polyacrylamide gel electrophoresis, which separates protein components of crude dynein fraction (Fraction I by Gibbons) derived from Tetrahymena cilia. By this method, the fraction was separated into three protein components (designated as bands I, II and III) on the gel. When the gel was actively stained for dynein ATPase, a single band appeared, which coincided with the position of band I. A purified dynein prepared by controlled pore glass (CPG-10) column chromatography and followed by Biogel A-15m filtration showed one band on the gel at the same position as band I. These results suggest that among these three protein components, band I represents dynein and bands II and III are derived form non-ATPase protein. 'Burstic phenomenon' was also observed on their ATPase activity when axoneme or crude dynein fractions were used for ATPase assay, while the phenomenon was almost extinguished when partially purified dynein after controlled pore glass column chromatography was used as sample.     

IUB commission of editors of biochemical journals the citation of bibliographic references in biochemical journals recommendations (1971)

A pentose-rich acidic glycoprotein was isolated from protease digested bovine vitreous humor by fractionation on an AG1-X2 column using NaCl solution gradient.The material eluted at 0.35 M NaCl (glycoprotein) was electrophoretically heterogeneous at pH 8.6 after partial purification on Sephadex G-25. Gel filtration on G-100 resolved the glycoprotein into two fractions. These fractions differ in molecular weight; mol. wt approx. 95 000 material consisted of two components on electrophoresis and mol. wt approx. 28 000 material showed only a single component on electrophoresis. The lower molecular weight component was re-chromatographed on Sephadex G-100 yielding a single orcinol positive component which gave a homogeneous band on gel electrophoresis.Quantitative analysis of this material gave 30% protein, 7.0% pentose, 18.7% glucosamine, 9.2% galactosamine, 10.9% hexuronic acid and 16.1% hexose.Treatment with 0.5 M NaOH at 20°C for 24 h resulted in a 50% decrease in the threonine content suggesting the possible involvement of this amino acid in the protein-carbohydrate linkage group.Paper chromatography of the fraction hydrolysate demonstrated the presence of glucurone, xylose, arabinose, glucose and galactose.     

Substructure of the Cytoplasmic Membrane of Bacillus megaterium

The components of fractions obtained by dialyzing and differential centrifuging the “Ghost” of Bacillus megaterium were analyzed in detail. The compositions of amino acids in the main fractions (Fraction 2 and 3) of the “Ghosts”, were estimated. Fraction 2 was rich in non-polar amino acids, while Fraction 3 was scanty of them. Most of the fatty acids in Fraction 2 were 12-methyl tetradecanoic acid, while in Fraction 3 many kinds of fatty acid were detected.

As for the localization of enzymes, the three enzymes, glucose oxidase, succinic dehydrogenase and reduced nicotinamide-adenine dinucleotide oxidase, which were present in the original “Ghosts”, were mostly observed in Fraction 2, and a very little amount of them was found in the other fractions. Further, Fraction 2 could be dissolved in formic acid and dialysis of the solution brought about reaggregation to form membrane-like structure in the presence of Ca or Mg ion.     

Separation of Component-Polypeptides of Glutenin by Isoelectric Focusing

1. By isoelectric focusing S-cyanoethyl glutenin was observed to be composed of various component-polypeptides having a pI spectrum in a pH range from 6 to 9.

2. During isoelectric focusing a precipitation zone was built up in the column in spite of the presence of 6 m urea. The amount of the precipitate formed was less with S-cyanoethyl glutenin than with S-sulfo glutenin.

3. S-Cyanoethyl glutenin was divided into eight fractions by isoelectric focusing. By starch-gel electrophoresis it was suggested that Fractions I, III and P were mainly composed of a single component.

4. Major N-terminal amino acids of Fractions I, III and P were phenylalanine, glycine and alanine, respectively. In the amino acid composition, distinct differences were observed in the respective fractions, especially in Fraction P. Fraction P showed a much higher content of basic amino acids and a lower content of glutamic acid in comparison with the other two.     

Acid hydrolysis of protein in a microcapillary tube for the recovery of tryptophan

The acid hydrolysis of proteins was miniaturized and simplified by employing microcapillary tubes (100 microl in volume) with 6 M HCl containing 1% 2-mercaptoethanol and 3% phenol for an amino acid compositional analysis. The method not only eliminated the laborious evacuation step for the hydrolysis tube but also decreased the destruction of tryptophan during hydrolysis. The recovery of tryptophan was 79% by acid hydrolysis at 145 degrees C for 4 h. Since the acid mixture could be removed under vacuum, the hydrolysate was subjected to an amino acid analysis without neutralization or dilution.     

Biochemical and Genetic Evidence of Enterocin P Production by Two Enterococcus faecium-Like Strains Isolated from Fermented Sausages

Two bacteriocin-producing Enterococcus faecium-like strains were independently isolated from fermented sausages. Bacteriocins were purified to homogeneity by ammonium sulfate precipitation, gel filtration, cationic exchange, hydrophobic interaction, and reverse-phase liquid chromatography. Two peptide inhibitory fractions were purified from each strain, denominated A and B for E. faecium AA13, and C and D for E. faecium G16. Fraction B was blocked for amino acid sequencing by Edman degradation, while the amino acid sequences obtained from peptides A, C, and D contained the YGNGV consensus motif in positions 5 to 9, and the ATRS sequence in positions 1 to 4. By use of PCR techniques and nucleotide sequencing, the structural gene of enterocin P was found both in E. faecium AA13 and E. faecium G16. Metabolic and genetic features of the two strains suggest that they are slightly different, they may produce more than one bacteriocin, and both produce enterocin P. Received: 13 May 1999 / Accepted: 22 June 1999     

ISOLATION AND CHARACTERIZATION OF PLASMA MEMBRANE FRACTIONS FROM GARFISH LEPISOSTEUS OSSEUS OLFACTORY NERVE

Garfish Lepisosteus osseus olfactory nerve, because of its large size and the unusually high concentration of axonal membrane, is an excellent source of axonal membrane. A procedure is described for the isolation of two types of plasma membranes from the nerve which are obtained in yields of about 20 mg (fraction I) and 1.5 mg (fraction II) per g of wet nerve. Both membrane fractions consist mostly of rounded membrane vesicles, with a unit membrane thickness of ~7.5 nm. The two membrane fractions are different in their lipid to protein ratios, Na-K ATPase activities, polypeptide patterns on sodium dodecyl sulfate (SDS) gel electrophoresis, and fatty acid compositions. They have similar phospholipid composition. On the basis of the relative concentration of axonal and Schwann cell plasma membranes in the nerve, the Na-K ATPase activities of the two membrane fractions and a comparison of the properties of the membrane fractions to those of squid and lobster nerve membrane preparations, fraction I seems to be the axonal membrane and fraction II the Schwann cell plasma membrane. Fraction I has a low protein to lipid ratio. Its polypeptide pattern on SDS gel appears to be much more complex as compared to that of fraction II membrane.     

Primary structure of bovine erythrocyte carbonic anhydrase CI. I. Tryptic peptides]

Bovine erythrocyte carbonic anhydrase CI consists of 259 amino acid residues including 18 lysines and 9 arginines. Its primary structure has been first investigated by isolation and sequence determination of the tryptic units. Acidification of the tryptic hydrolysate leads to the precipitation of 40% of the peptidic material. All the acid soluble peptides were isolated from the supernatant by chromatography on Dowex 50 W-X2 and Dowex 1-X2 followed by purification of heterogeneous fractions. Two of the three acid insoluble peptides were obtained in a pure form from the whole tryptic hydrolysate by gel filtration on Sephadex G-50 and chromatography on DEAE-Sephadex in alkaline medium. The sequence of the so isolated tryptic units has been determined with the exception of two of them obtained in a very poor yield.