M-acetic Acid Research Articles

The Organosolv Fractionation of Cork Components

Summary Extractive-free cork from Quercus suber L. was submitted to organosolv fractionation and the effects of different process variables, such as ethanol/water ratio, temperature, time and the presence of acidic or alkaline catalysts, were studied. The variation of the relative proportions of extracted components, as a function of the processing conditions, could thus be established. Whereas the addition of 0.1Macetic acid only increased the yield of extracted materials from about 15 to 23 %, the use of sodium hydroxide, at the same concentration, produced a jump to 76 %. In the case of the alkaline organosolv fractionation, an increase in process temperature, time and catalyst concentration led to an increase in the extraction yield, although in some cases this increase did not follow a sustained trend, as in the case of reaction time. Increasing the ethanol/water ratio led to a higher selectivity in favour of suberin extraction. Residual cork from different organosolv processes was characterised by FTIR and 13C solid-state NMR. The latter technique provided some valuable information about both process selectivity and cork morphology, particularly with respect to the positioning of suberin macromolecules in the cell wall.

Small-angle X-ray-scattering studies of the C hordeins of barley (Hordeum vulgare)

Small angle X-ray scattering was used to study the solution conformation of the C hordeins of barley (Hordeum vulgare), a group of proteins whose primary structure consists predominantly of an octapeptide repeat motif. Measurements on the protein in 0.1 M-acetic acid at 25 degrees C are consistent with a model for the protein conformation of a stiff coil, the so-called 'worm-like' chain. The characteristic parameters (the Kuhn statistical segment length and the contour length) of the protein were calculated as 5.11 and 71.5 nm respectively.

Factors in ruminant colostrum that influence cell growth and murine IgE antibody responses.

Bovine colostrum was investigated as a source of biologically active molecules capable of stimulating the growth of mammalian cells in culture and modifying the immune response in a murine model. An extract prepared from bovine colostral whey by cation exchange and reversed-phase chromatography stimulated the growth of L6 rat myoblasts, Balb/c-3T3 mouse fibroblasts and BHK-21 baby hamster kidney cells with equal or greater potency than fetal bovine serum. Fractionation of the bovine colostral extract by gel-permeation chromatography in M-acetic acid identified a number of cell-growth factors for each cell type. Bovine colostral extract was compared with an ovine colostral whey preparation for its ability to modulate IgE antibody responses in mice. Doses of 8 and 4 mg/d of ovine colostral whey or bovine colostral extract specifically suppressed IgE antibody responses, whereas at lower doses suppression did not occur. We conclude that bovine colostrum contains cell-growth factors as well as immunomodulatory factors that are able to regulate the IgE response in a heterologous species.

Gene synthesis, expression in Escherichia coli, purification and characterization of the recombinant bovine acyl-CoA-binding protein

A synthetic gene encoding the 86 amino acid residues of mature acyl-CoA-binding protein (ACBP), and the initiating methionine was constructed. The synthetic gene was assembled from eight partially overlapping oligonucleotides. Codon usage and nucleotides surrounding the ATG translation-initiation codon were chosen to allow efficient expression in Escherichia coli as well as in yeast. The synthetic gene was inserted into the expression vector pKK223-3 and expressed in E. coli. In maximally induced cultures, recombinant ACBP constitutes 12-15% of total cellular protein. A fraction highly enriched for recombinant ACBP was obtained by extracting induced E. coli cells with 1 M-acetic acid. Recombinant ACBP was purified to homogeneity by successive use of gel-filtration chromatography, ion-exchange chromatography and reverse-phase h.p.l.c. Recombinant ACBP differed from native ACBP by lacking the N-terminal acetyl group. The acyl-CoA-binding characteristics of recombinant ACBP did not differ from those of native ACBP, and the two proteins showed the same ability to induce medium-chain acyl-CoA synthesis by goat mammary-gland fatty acid synthetase. It was concluded that the N-terminal acetyl group is not important for acyl-CoA binding.

Polypeptide formation by heating aqueous solution of amino acids and peptides

It is considered that there were several possible pathways in which polypeptides were produced on premitive earth. Of these pathways, (i) condensation of solid amino acids on heating, (2) condensation of amino acids in aqueous media over condensing agents or (3) on heating are known. The first one has been studied in detail(Fox et al., 1960). The second one has not given longer peptides than 5 residues(Hulshof et al., 1976). However, there are a few reports related to the third one in which much larger peptides were obtained from aspargine with the molecular weight more than c.a. 3000(Kovacs et al., 1961.; Harada et al., 1978). In this paper, we wish to describe the role of aspargine and glutamine having 8 or y primary amide for polypeptide formation in the hypothetical premitive ocean. We carried out the heating of aqueous solution contaning aspargine and other amino acids(glycine, alanine, and valine) or peptides which have asparagine or glutamine residue in the C-terminal. Heatin @ reaction of aqueous solution of as~arqine and some other amino acids. Five mmol L-aspargine monohydrate(750mg) and other amino acids[0.5-2.5 mmol(Gly, Ala, Val)]were dissolved in 5 ml H20 , and the solutions sealed in vacuo in a glass tube were heated at 120°C for 2-200 hr. After the reactions, the reaction solution was analyzed by amino acid analyzer and remaining sample was loaded into a Sephadex G-15 column. The elution was carried out with 0.5 M-acetic acid to give white amorophous powder. The 32 hours' reaction mixtures gave muximum isolated yield(>90mg). The IR of this compound showed typical acidic polypeptide absorption(1710, 1650, 1540 cm-l). Averaged molecular weight of this peptide was estimated to be 1500-3000 by gel filtration. Molar composition of the amino acids contained in the copolyamino acids were almost pallarel to the first composition of the reaction mixtures, when the molar ratio of other amino acid to L-aspargine was lower than 50 %. Heating reactions of amino acid solutions without aspargine

Chitin Synthase Activity from Neocallimastix frontalis, an Anaerobic Rumen Fungus

Chitin synthase activity was detected in actively growing mycelium of Neocallimastix frontalis after mechanical disruption of the cells. Chitin formation in fungal extracts at 32 °C was linear with respect to time for at least 60 min, and with respect to protein concentration up to 750 μg ml−1. The optimum pH for enzyme activity was 8·5 using 10 mm-Tris/HCl buffer. Mg2+ was necessary for maximum activity and 10 mm-MgC12 was routinely used during the assays. The apparent K m for the substrate UDP-GlcNAc was 2 mm. Polyoxin D was a competitive inhibitor of chitin synthesis with an apparent K i of 4 μm. Following treatment with trypsin (12·5 μg ml−1), the chitin synthase activity of the fungal extract increased by six-fold, indicating that most of the chitin synthase activity was zymogenic. The reaction product was insoluble in 1 m-KOH or 1 m-acetic acid, but it was solubilized by heating in 6 m-HCl at 120 °C for 2.5 h and was hydrolysed by chitinase into diacetylchitobiose.

Purification and biochemical characterization of three major acidic proteins (BSP-A1, BSP-A2 and BSP-A3) from bovine seminal plasma.

Three major acidic proteins of bovine seminal plasma, BSP-A1, BSP-A2 and BSP-A3, were purified to homogeneity, by employing fast protein liquid chromatography, gel filtration and h.p.l.c. The proteins were purified on the basis of their stimulatory effect on the basal release of gonadotropins by rat anterior-pituitary cells in culture. All three proteins migrated as distinct single bands in the presence or absence of 2-mercaptoethanol in SDS/polyacrylamide-gel electrophoresis. Their Mr values were estimated to be between 15,000 and 16,500 by SDS/polyacrylamide-gel electrophoresis. Similar Mr estimates were obtained when they were subjected to gel filtration on a calibrated column of Sephadex G-75 equilibrated in 0.05 M-acetic acid, pH 3.0. However, BSP-A1 and BSP-A2 were eluted as aggregated molecules (Mr 60,000-120,000) during gel filtration on Sephadex G-200 equilibrated in 0.05 M-NH4HCO3, pH 8.5, or phosphate buffer, pH 7.0, containing 0.15 M-NaCl. In the presence of 8 M-urea both BSP-A1 and BSP-A2 were eluted at positions corresponding to Mr values of 17,000-20,000. BSP-A1 and BSP-A2 had an identical amino acid composition, which differed largely from that of BSP-A3. All three proteins contained aspartic acid as the N-terminal residue, and cysteine was identified as the C-terminal residue. BSP-A1 and BSP-A2 are glycoproteins containing galactosamine, sialic acid and neutral sugars, but BSP-A3 did not contain any covalently attached sugars. Whereas BSP-A2 and BSP-A3 were eluted unadsorbed, BSP-A1 bound to wheat-germ lectin-Sepharose 6MB and could be eluted by the competing sugar N-acetyl-D-glucosamine. Treatment of BSP-A1 and BSP-A2 with trypsin resulted in complete loss of gonadotropin-release activity, but BSP-A3 retained full activity. Antibody raised against BSP-A1 did not cross-react with BSP-A3, or vice versa. All these properties indicated marked structural differences between BSP-A3 and BSP-A1 (or BSP-A2). On the basis of amino acid composition it was concluded that BSP-A1, BSP-A2 and BSP-A3 are the same as the gonadostatins [Esch, Ling, Bohlen, Ying & Guillemin (1983) Biochem. Biophys. Res. Commun. 113, 861-867].

The stability of 5-hydroxyindoleacetic acid and noradrenaline in normal and Alzheimer post mortem brain

of Huntington and Parkinson (Bernheimer et al., 1973; Spokes, 1980). Because of the post mortem instability of biosynthetic marker enzymes, such studies have relied upon determination of the concentration of transmitter amines and their metabolites. By contrast, there have been few similar studies of cortical regions, largely because of the relatively low concentrations of the transmitters and some of their metabolites. The present study takes advantage of recent advances in h.p.1.c. technology in order to measure neocortical concentrations of 5hydroxytryptamine (5-HT) and noradrenaline (NA) and their major metabolites, 5-hydroxyindoleacetic acid (5HIAA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) respectively. The post mortem stability of these compounds has been examined by comparing the concentrations in tissue obtained post mortem and during life. Tissue from the fronto-temporal lobes was obtained at neurosurgery, as previously described (Sims et al., 1981), from 79 patients (aged 8-74 years) undergoing treatment for tumours or aneurysm, where the removal of apparently normal tissue was a necessary part of the surgical procedure. Tissue from the same lobes was obtained post mortem from 34 subjects (aged 38-99 years; postmortem delay 4-72 h) free of neurological or psychiatric illness, as described elsewhere (Francis et al., 1985). All samples were stored frozen (70°C or less) and neurosurgical tissue (30-60 mg) and post mortem tissue (1 00-200 mg) homogenized in acid (1 M-acetic acid for MHPG and 0.4 M-perchloric acid for all other compounds) containing 1 mwcysteine and I ~ M E D T A together with an appropriate internal standard (3,4-dihydroxybenzylamine, a-methyldopamine or vanillic acid). After centriof many studies, most nota ! ly with regard to the diseases

Production and characterization of antibodies against murine dentine phosphoprotein.

Experiments were designed to produce and characterize a polyclonal antibody directed against mouse dentine phosphoprotein, the major non-collagenous protein of the dentine extracellular matrix. Dental extracellular matrix proteins from 2-day-postnatal Swiss-Webster-mouse tooth organs were extracted with 0.5 M-acetic acid, followed by 4 M-guanidinium chloride/0.5 M-EDTA. Mouse dentine phosphoprotein yields were further increased by precipitation with 1 M-CaCl2. Final purification was achieved by excising and eluting dentine phosphoprotein polypeptide bands from preparative sodium dodecyl sulphate/urea/polyacrylamide gels. Mouse dentine phosphoprotein is a single component of approx. 72 kDa and has a characteristic amino acid composition of 33% aspartic acid and 55% serine/phosphoserine. A polyclonal antibody was raised in rabbits against purified mouse dentine phosphoprotein and was shown to be monospecific by enzyme-linked immunoabsorbent, dot-immunobinding and 'Western transfer' assays. This antibody was used to detect the expression and localization of dentine phosphoprotein in 1-day-postnatal mouse tooth organs. This antigen was localized intracellularly within the monolayer of odontoblasts, which line the perimeter of the dental papilla mesenchyme, and within the odontoblastic cell processes, which traverse the predentine matrix. Newly forming mineralized dentine matrix was also cross-reactive with the dentine phosphoprotein specific antibody. The non-mineralized predentine matrix did not contain any detectable cross-reactive antigens.

Isolation and identification of large overlapping fragments of rabbit myelin basic protein produced by limited peptic hydrolysis.

Treatment of rabbit myelin basic protein component 1 with pepsin (enzyme:substrate, 1:500 w/w) in 0.5 M-ammonium formate (pH 6.00) for 15-20 min at room temperature resulted in limited cleavage of the protein. The resulting fragments were isolated by ion-exchange chromatography and gel filtration and identified by amino acid and COOH-terminal analyses and by tryptic peptide mapping. All of the possible products resulting from incomplete cleavages at the highly susceptible Phe44-Phe45, Phe87-Phe88, Leu109-Ser110, and Leu151-Phe152 bonds were isolated: peptides (1-151), (1-109), (1-87), (45-168), (45-151), (45-109), (88-168), (88-151), and (110-168). Of these, peptides (1-151), (1-87), and (88-151) were recovered in the greatest yield (0.14-0.19 mol per mol of starting protein). Relatively low yields (0.04 mol/mol starting protein) were obtained for peptides (1-109) and (110-168), indicating that the Leu109-Ser110 bond is somewhat more resistant to peptic cleavage than are the Phe-Phe and Leu-Phe bonds. Smaller fragments of the basic protein were also recovered: peptides (1-44), (1-28), (45-87), (88-109), (110-151), and (152-168). Many of the individual peptides could be readily identified in electrophoretograms of the total peptic digest. The relative electrophoretic mobilities of the above-mentioned peptides, together with the previously isolated peptides (1-14) and (15-44), were determined in 15% (w/w) polyacrylamide slab gels containing 1 M-acetic acid and 8 M-urea.

Alkali-labile oligosaccharides from glycopeptides of human milk-fat-globule membrane

In view of its origin in the apical membrane of the mammary secretory cell (Patton & Keenan, 1975), the milk-fat-globule membrane is of interest as a relatively readily acessible source of mammalian epithelial membrane for structural and immunological studies. The bovine milk-fat-globule membrane, particularly, has been analysed, and a number of reports have described its glycoprotein components (Kobylka & Carraway, 1972: Anderson et al., 1974; Murray et al., 1979). which have been shown to carry relatively large amounts of the alkalilabile tetrasaccharide N-acetylneuraminyl-(2+3)-~-~-galactopyranosyl (1 -3) [ N acetylneuraminyl(2+6)1Nacetyl D galactosamine (Newman et al., 1976; Farrar & Harrison, 1978). This tetrasaccharide was originally described by Thomas & Winzler (1969) as a component of human erythrocyte membranes and has been also detected on membranes of rat brain (Finne, 1975), liver and kidney (Krusius & Finne, 1977), and on erythrocyte membranes from horse and sheep (Glockner et al., 1976). The human milk-fat-globule membrane is less readily available on a large scale and has been correspondingly less studied. Nevertheless, electrophoretic patterns of human milk-fatglobule-derived glycoproteins have been compared with those of their bovine counterparts and species differences were observed in the abilities of the glycoproteins to interact with certain lectins (Murray et al., 1979). Moreover, differences have been detected in the carbohydrate components of glycoproteins derived from human and bovine milk-fat-globule membranes (Glockner et al., 1976: Newman & Uhlenbruck, 1977) and also on the exposed surfaces of the globules themselves (Farrar et al., 1980). We now report the preparation and fractionation of glycopeptides proteolytically cleaved from the surface of intact human milk-fat globules and the release of relatively complex oligosaccharide complexes by treatment of the glycopeptides with alkaline borohydride. Freshly-expressed human breast milk (1.5 litres) was centrifuged and washed repeatedly in double-distilled water to give washed fat globules (50g), which were incubated with Pronase at 37OC for 1 h, cooled, centrifuged and dialysed to give a solution of sialoglycopeptides containing approx. 8 mg of hexose and 1.25 mg of sialic acid. The soluble sialoglycopeptides were fractionated by gel filtration on Sephadex G-50, when two major hexose/sialic acid peaks, peaks I and 11, were obtained, containing 20 and 80% repsectively of the total sialic acid applied to the column. Fractions corresponding to peak I1 were combined and applied to a column of Sephadex G-25. Elution with 0.1 M-acetic acid gave an excluded peak, fractions from which were combined so as to exclude a minor tail of hexose/sialic acid material. The pooled fractions were freeze-dried, treated with alkaline borohydride, freed from inorganic salts and rechromatographed on Sephadex G-25 as described above. Fractions eluted after the excluded peak were combined, freeze-dried and applied to a column of DEAE-Sephadex A-25. Elution with 0.05 M-pyridine acetate, followed by a linear gradient (0.05-0.65 M) of pyridine acetate, gave three hexose/ sialic acid peaks (HA, IIB and IIC), only the first (IIA) of which contained protein. Fractions corresponding to peak IIB, the larger of the protein-free peaks were combined, freeze-dried and chromatographed on preparative thin-layer plates of silica-gel G (development was with propan-2-ol/butan-2-ol/water), when two major bands, with R, 0.19 and 0.15 respectively, were obtained. The combined bands were eluted from the gel, freeze-dried and analysed for monosaccharide composition by using gas chromatography, when sialic acid, galactose, Nacetylglucosamine and N-acetylgalactosamine were found to be present in the molar ratio 6 : 7 : 4 : 2. Alkali-labile oligosaccharides released from mammalian membrane glycoproteins and fully characterized have largely been found to be structurally derived from the tetrasaccharide named above, which contains just sialic acid, galactose and N-acetylgalactosamine. Indications of more complex structures, containing glucosamine, have been obtained from bovine erythrocytes (Emerson & Kornfeld, 1976; DeWaard et al., 1976; Newman & Uhlenbruck, 1977), and it may be that such complexes, present also on human milk-fat-globule membranes, are more common than has been hitherto appreciated.

The release of rat intestinal cholecystokinin after oral trypsin inhibitor measured by bio-assay.

The distribution, molecular form and release of cholecystokinin (CCK)-like activity in extracts of rat small intestine was studied with an in vitro gall-bladder bio-assay. In contrast to the reported heterogeneity of CCK-like immunoreactivity in the intestine, only a single molecular form of CCK-like activity was detected using the bio-assay. 2. The CCK-like activity eluted from Sephadex G50 with a Kav of 0.69, after the triacontriapeptide of cholecystokinin (CCK33) and before cholecystokinin octapeptide 2500, may represent the 22 amino acid peptide of CCK (CCK22). The bio-assay peak of CCK-like activity had pancreozymin activity and CCK/gastrin C terminal immunoreactivity. The CCK-like activity weas readily extracted from the small intestine at neutral pH, but subsequent treatment with cold 0.5 M-acetic acid extracted further CCK-like activity of the same molecular form as that recovered under neutral conditions. 3. The bio-assay detected no CCK-like activity, nor was pancreozymin-like activity found in fractions corresponding to CCK33 or CCK8 after Sephadex G50 chromatography of rat intestinal extracts. 4. Oral trypsin inhibitor was a potent stimulus for the release of CCK-like activity from the upper small intestine of the rat. After oral trypsin inhibitor release, CCK-like activity was rapidly resynthesized.

Sequential extraction techniques applied to a porphyry copper deposit in the basin and range province

Samples of minus-80-mesh (<180 μm) stream sediment, rock containing exposed fracture coatings, and jarosite and chrysocolla were collected from an area surrounding the North Silver Bell porphyry Cu deposit near Tucson, Arizona. The samples were subjected to a series of extractions in a scheme originally designed for use on samples from humid or sub-humid environments, in which the following fractions can effectively be separated: (1) carbonates and exchangeable metals; (2) Mn oxides; (3) organic compounds and sulfides; (4) hydrous Fe oxides; and (5) residual crystalline minerals. Jarosite and chrysocolla, two major minerals of the North Silver Bell area, were found to dissolve over two or more steps of the extraction scheme. The results represent only a limited number of samples from one copper deposit. Nevertheless, they do suggest that in a semiarid to arid environment, where mechanical dispersion of such minerals predominates, uncritical assignment of unique phases, such as Mn oxides or organics to a given extraction would lead to false interpretations of weathering processes. However, the relative proportions of elements dissolved in each step of the jarosite and chrysocolla extractions could be used as a “fingerprint” for recognition of the presence of these two minerals in the stream-sediment and rock samples. The relative abundance of hydrous Fe oxide and jarosite and the alteration zoning could be mapped using data from jarosite and chrysocolla extractions. Manganese oxides were also found to have a greater influence on Zn than on Cu or Pb during supergene alteration. The rapid change in relative importance of the first (1 M-acetic acid) extraction for Cu, Zn, and Pb near the mineralized zone suggested the occurrence of minor hydromorphic processes within the stream sediments. Thus, the acetic acid extraction proved the most effective for pinpointing mineralization in sediments. In contrast, the residual fraction had the longest dispersion train, suggesting that total metal concentrations are most effective in arid environments for reconnaissance surveys.

The anion-transport protein of the human erythrocyte membrane. Studies on fragments produced by pepsin digestion

We have studied the fragmentation by pepsin in 1 M-acetic acid of the erythrocyte anion-transport protein in erythrocyte membranes. The location of the fragments obtained was determined by radioiodinating the protein with the use of lactoperoxidase, and identifying the labelled peptides obtained in peptide "maps" of thermolysin digests of the fragments. Three of the fragments were found to be related overlapping products, and shared a common C-terminus. The major site of pepsin cleavage leading to the C-termini of these fragments was shown to be close to the major site of extracellular cleavage of the protein by proteinases active at a neutral pH. Another two fragments were isolated and shown to be derived from the C-terminal portion of the protein. No well-defined large radioactive fragments of the protein were solubilized from the membrane by pepsin in 1 M-acetic acid, the bulk of the radioactivity attributable to the anion transport protein being recovered in very small fragments that could not be resolved by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Our results suggest that the polypeptide chain of the anion-transport protein emerges at the extracellular face of the membrane 8000-13000 daltons on the N-terminal side of the major site of extracellular cleavage of the protein by proteinases that are active at a neutral pH.

Platelet-aggregating activity of type I and type III collagens from human aorta and chicken skin.

Human or chicken type III collagen dissolved in 0.1 M-acetic acid was much more potent than type I collagen at inducing platelet aggregation. After incubation in 0.38M-Na2HPO4 to promote fibrillogenesis, the platelet-aggregating activity of both collagen types increased, and type I was then virtually equiactive with type III. Preincubation in cell-free plasma increased the activity of chicken but not that of human collagen. The platelet-aggregating activity of type III collagen did not appear to depend on the integrity of the intrachain disulphide bonds.

Insulin Biosynthesis in a Broken-Cell Preparation of Islets of Langerhans

Conference Article| December 01 1975 Insulin Biosynthesis in a Broken-Cell Preparation of Islets of Langerhans DAVID G. PARRY; DAVID G. PARRY 1Biochemistry Group, School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, U.K. Search for other works by this author on: This Site PubMed Google Scholar KEITH W. TAYLOR KEITH W. TAYLOR 1Biochemistry Group, School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, U.K. Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1975) 3 (6): 903–904. https://doi.org/10.1042/bst0030903 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation DAVID G. PARRY, KEITH W. TAYLOR; Insulin Biosynthesis in a Broken-Cell Preparation of Islets of Langerhans. Biochem Soc Trans 1 December 1975; 3 (6): 903–904. doi: https://doi.org/10.1042/bst0030903 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search This content is only available as a PDF. © 1975 Biochemical Society1975 Article PDF first page preview Close Modal You do not currently have access to this content.

Electrodialytic Extraction in Drug Analysis. I. Description of Apparatus and Study of Extraction Condition

A new method of extraction, i. e. electrodialytic extraction was proposed. Electrodialytic extraction apparatus was also devised. Extraction conditions were examined and the following results were obtained.1. Electrodialytic extraction was more effective than shaking extraction.2. Possibility of electrodialytic extraction of a test component could be demonstrated by using a liquid sample.3. Acetic acid (0.5M) was chosen as the acidic standard carrier solution.4. A suitable current density was 20mA/cm2 when using this apparatus and 0.5Macetic acid as the carrier solution.5. It is desirable for the carrier solution to be a weak electrolyte with specific conductivity of about 1×10-3mho/cm.6. Change in quantity of sample required no essential prolongation of extraction time.7. The suitable particle size of the sample was about 100 mesh.8. Cellulose membrane was chosen as the dialysis membrane for extracting low molecular compounds.