scholarly journals Preparation of high Fischer ratio oligopeptide by proteolysis of corn gluten meal

2008 ◽  
Vol 26 (No. 1) ◽  
pp. 38-47 ◽  
Author(s):  
Ma Ying ◽  
Lin Li ◽  
Sun Da-Wen
Keyword(s):  
Amino Acid ◽  
Gel Filtration ◽  
Aromatic Amino Acids ◽  
Enzyme Reaction ◽  
Ion Exchange Resin ◽  
Orthogonal Experimental Design ◽  
Degree Of Hydrolysis ◽  
Corn Gluten Meal ◽  
Molecular Weights ◽  
Corn Gluten

A method to obtain an oligopeptide with high Fischer ratio is described. Corn gluten meal (CGM) was hydrolysed with Alcalase 2.4L using a two-step hydrolysis. In the first-step hydrolysis, the enzyme reaction conditions for hydrolysing CGM were optimised by using the orthogonal experimental design, while pH = 8.0, temperature = 55°C, enzyme to substrate ratio (3:97, w/w), and the substrate concentration = 5% were identified as the optimum conditions, under which up to 11.62% degree of hydrolysis (DH) could be obtained. The hydrolysate was then fractionated by ultrafiltration using a membrane with the molecular cutoff of over 10 kD at 20 kPa. For the second-step hydrolysis, the filtrate was adjusted to pH 6.0, then papain was added at 50°C and the mixture was maintained for 3 hours. The hydrolysate was obtained after inactivating papain and centrifuging. Then the salt (mainly NaCl) in the hydrolysate was removed with an ion exchange resin at the speed of 8 times bed volume per hour, and aromatic amino acids were removed through absorption by active carbon. By using Sephadex G-25 gel filtration chromatography, a peptide mixture with low molecular weights between 1000 and 1300 was obtained. Finally, tests on amino acid composition and free amino acid concentration of oligopeptide solution showed that the oligopeptide had a high Fischer ratio of 34.71 and the yield of 11.59%.

Characterization of an isozyme of S-adenosylmethionine synthetase from rat liver

1984 ◽  
Vol 62 (5) ◽  
pp. 276-279 ◽  
Author(s):  
C. H. Lin ◽  
W. Chung ◽  
K. P. Strickland ◽  
A. J. Hudson
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Enzymatic Synthesis ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Aromatic Amino Acids ◽  
Adenosylmethionine Synthetase ◽  
Cellulose Column

An isozyme of S-adenosylmethionine synthetase has been purified to homogeneity by ammonium sulfate fractionation, DEAE-cellulose column chromatography, and gel filtration on a Sephadex G-200 column. The purified enzyme is very unstable and has a molecular weight of 120 000 consisting of two identical subunits. Amino acid analysis on the purified enzyme showed glycine, glutamate, and aspartate to be the most abundant and the aromatic amino acids to be the least abundant. It possesses tripolyphosphatase activity which can be stimulated five to six times by S-adenosylmethionine (20–40 μM). The findings support the conclusion that an enzyme-bound tripolyphosphate is an obligatory intermediate in the enzymatic synthesis of S-adenosylmethionine from ATP and methionine.

Effect of extractant and molecular size on the optical and chemical properties of soil humic acids

Soil Research ◽  
1969 ◽  
Vol 7 (3) ◽  
pp. 229 ◽  
Author(s):  
JHA Butler ◽  
JN Ladd
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Humic Acids ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Molecular Size ◽  
Carboxyl Content ◽  
Peptide Bonds ◽  
Molecular Weights ◽  
Amino Acid Contents

Humic acids extracted from soil with sodium pyrophosphate have greater proportions of lower molecular weight material, less acid-hydrolysable amino acid nitrogen contents, but greater carboxyl contents and extinction values (260 and 450 nm) than humic acids extracted subsequently from the same sample with alkali. Humic acids extracted with alkali from fresh soil samples have intermediate values. Extinction values at 260 nm are directly correlated with carboxyl contents for a given soil. Different crop histories have no significant effect on the measured properties of the extracted humic acids. An alkali-extracted humic acid has been fractionated by gel filtration into seven fractions of different nominal molecular weight ranges. As the molecular weights of the fractions increase, both aliphatic C-H (based on infrared absorption at 2900 cm-1) and acid-hydrolysable amino acid contents increase, whereas extinction values at 260 nm and carboxyl contents decrease. The infrared spectra of the high molecular weight fractions have peaks at 1650 and 1510 cm-1 which correlate with acid-hydrolysable amino acid contents and which correspond to amide I and II bands of peptide bonds. Alkaline hydrolysis to split peptide bonds eliminates both these peaks. The spectra also have peaks at 1720 and 1210 cm-1 which correlate with the carboxyl content.

scholarly journals α-Crystallin. The isolation and characterization of distinct macromolecular fractions

1971 ◽  
Vol 124 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Abraham Spector ◽  
Lu-Ku Li ◽  
Robert C. Augusteyn ◽  
Arthur Schneider ◽  
Thomas Freund
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Chemical Difference ◽  
Molecular Weights ◽  
Isolation And Characterization ◽  
Different Populations ◽  
Molecular Weight Fractions

α-Crystallin was isolated from calf lens periphery by chromatography on DEAE-cellulose and gel filtration. Three distinct populations of macromolecules have been isolated with molecular weights in the ranges approx. 6×105−9×105, 0.9×106−4×106and greater than 10×106. The concentration of macromolecules at the molecular-weight limits of a population are very low. The members of the different populations do not appear to be in equilibrium with each other. Further, in those molecular-weight fractions investigated, no equilibrium between members of the same population was observed. The population of lowest molecular weight comprises 65–75% of the total material. The amino acid and subunit composition of the different-sized fractions appear very similar, if not identical. The only chemical difference observed between the fractions is the presence of significant amounts of sugar in the higher-molecular-weight fractions. Subunit molecular weights of approx. 19.5×103and 22.5×103were observed for all α-crystallin fractions.

Cellular Amino Acid Concentrations and Regulation of Aspartate Kinase in the Thermophilic Phototrophic Prokaryote Chloroflexus aurantiacus

1990 ◽  
Vol 45 (1-2) ◽  
pp. 74-78 ◽  
Author(s):  
Jobst-Heinrich Klemme ◽  
Gisela Laakmann-Ditges ◽  
Jutta Mertschuweit
Keyword(s):  
Amino Acid ◽  
Feedback Inhibition ◽  
Gel Filtration ◽  
Break Point ◽  
Test System ◽  
Chloroflexus Aurantiacus ◽  
Aspartate Kinase ◽  
Homoserine Dehydrogenase ◽  
Molecular Weights ◽  
Amino Acid Concentrations

Aspartate kinase (AK , EC 2.7.2.4) from the thermophilic, phototrophic prokaryote, Chloroflexus aurantiacus, was partially purified and separated from homoserine dehydrogenase (HSDH, EC 1.1.1.3). The molecular weights as determined by gel filtration were 130,000 and 46,000, respectively. HSDH had a moderately high thermal stability (50% inactivation at 84 °C) and displayed its activity optimum at 72 °C. By contrast, AK had its activity optimum at 52 °C (with a break-point in the Arrhenius plot at 42 °C) and was much less thermostable (50% inactivation at 67 °C). The Km-values for aspartate and ATP (determined in a pyruvate kinase-coupled test system) were 10.5 and 0.63 mM , respectively. The enzyme was strongly inhibited by L-threonine (Ki = 10 μm) and activated by alanine, isoleucine, valine and methionine. L-Threonine acted as a mixed-type inhibitor in respect to aspartate, and non-competitively in respect to ATP. Contrary to AKs from Rhodospirillaceae, the enzyme from Chloroflexus aurantiacus was not subject to a concerted feedback inhibition by two amino acids of the aspartate family. The regulatory properties of the aspartate kinase are discussed in relation to the cellular amino acid concentrations.

RATE OF PROTEIN DEGRADATION AND NUTRIENT DIGESTION OF VARIOUS NITROGEN SOURCES IN CONTINUOUS CULTURE OF RUMEN CONTENTS

1987 ◽  
Vol 67 (3) ◽  
pp. 745-756 ◽  
Author(s):  
J. E. GARRETT ◽  
R. D. GOODRICH ◽  
M. D. STERN ◽  
J. C. MEISKE
Keyword(s):  
Amino Acid ◽  
Protein Degradation ◽  
Continuous Culture ◽  
Soybean Meal ◽  
Nitrogen Sources ◽  
Total Amino Acid ◽  
Linseed Meal ◽  
Corn Gluten Meal ◽  
Corn Gluten ◽  
Dietary Amino Acid

A dual flow continuous culture fermentor system was used to estimate ruminal rate of protein degradation and influence of supplemental nitrogen (N) source on digestion of total dietary crude protein (CP), dry matter (DM) and organic matter (OM). Four experimental diets contained predominantly corn and were isocaloric (14.7 M J DE kg−1) and isonitrogenous (12% CP on a DM basis) with urea, soybean meal (SBM), linseed meal (LSM) or corn gluten meal (CGM) as sole supplemental N sources. Fermentor flow rates were adjusted daily to attain liquid and solid dilution rates of 10 and 5% h−1, respectively. Total dietary N digestibility was greater (P < 0.05) in fermentors receiving urea than in those receiving CGM, while fermentors receiving SBM or LSM were intermediate (72.9, 54.9, 64.0 and 63.2%, respectively). Bacterial CP flow was higher (P < 0.05) from fermentors receiving urea or SBM than from those receiving CGM, with fermentors receiving LSM intermediate (1.31, 1.29, 1.02 and 1.14 g d−1, respectively). True OM digestibility was greater (P < 0.05) for diets supplemented with urea or LSM than for those supplemented with CGM (65.1, 60.4 and 51.2%, respectively). The rate of protein degradation was greater (P < 0.05) for LSM-CP than CGM-CP with SBM-CP intermediate (15.73, 6.88 and 10.13% h−1, respectively). Calculated bypass of potentially digestible protein for SBM-CP, LSM-CP and CGM-CP was 15.9, 10.9 and 29.1%, respectively. Total amino acid flow (g d−1) was higher (P < 0.05) for fermentors receiving SBM than for those receiving LSM. Total bacterial amino acid flow (g d−1) was higher (P < 0.05) for fermentors receiving SBM than for fermentors receiving CGM. Differences among diets for dietary amino acid flow (g d−1) were not significant. Key words: Ruminal protein degradation, soybean meal, linseed meal, corn gluten meal, continuous culture system

scholarly journals The isolation of three neurophysins from porcine posterior pituitary lobes

1970 ◽  
Vol 116 (5) ◽  
pp. 899-909 ◽  
Author(s):  
L. O. Uttenthal ◽  
D. B. Hope
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Gel Filtration ◽  
Biological Significance ◽  
Starch Gel Electrophoresis ◽  
Posterior Pituitary ◽  
Fresh Tissue ◽  
Molecular Weights ◽  
Molecular Dimensions

1. Three neurophysins, proteins that bind the polypeptide hormones oxytocin and vasopressin, have been isolated from acetone-dried porcine posterior pituitary lobes. The proteins have been named porcine neurophysins-I, -II and -III in order of their electrophoretic mobilities at pH8.1. 2. Electrophoretic comparison of the purified proteins, which are homogeneous on starch-gel electrophoresis, with the soluble proteins of fresh porcine posterior pituitary lobes extracted in 0.1m-HCl and in buffer pH8.1 suggests that the isolated proteins are native to the fresh tissue. 3. Neurophysins-I and -II are present in similar amounts in the tissue, whereas neurophysin-III is present only in small quantities. Acetone-dried tissue also contains traces of other hormone-binding neurophysin components. 4. All the neurophysins can bind both oxytocin and [8-lysine]-vasopressin. 5. The apparent molecular weights of the neurophysins increase with increasing protein concentration as measured by equilibrium sedimentation in the ultracentrifuge. 6. Neurophysins-I and -III are of similar molecular dimensions, contain one residue of methionine per molecule and lack histidine. The minimum molecular weight of neurophysin-I obtained by amino acid analysis is 9360. Neurophysin-II is of larger molecular dimensions than neurophysins-I and -III and can be separated from these by gel filtration on Sephadex G-75. It contains no histidine or methionine, and its minimum molecular weight has been estimated as 14020 by amino acid analysis. 7. Each of the three neurophysins possesses N-terminal alanine. 8. The possible biological significance of the existence of several neurophysins within one species is discussed.

Comparison of some properties of soil humic acids and synthetic phenolic polymers incorporating amino derivaties

Soil Research ◽  
1966 ◽  
Vol 4 (1) ◽  
pp. 41 ◽  
Author(s):  
JN Ladd ◽  
JHA Butler
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Hydrolysis ◽  
Humic Acids ◽  
Gel Filtration ◽  
Quinone Imine ◽  
Peptide Bonds ◽  
Molecular Weights ◽  
Soil Humic Acids ◽  
Properties Of Soil

Twenty-three model phenolic polymers, either nitrogen-free or incorporating amino acids, peptides, or proteins, have been prepared from p-benzoquinone and catechol under mild oxidative conditions. Two lines of experimentation have demonstrated properties of soil humic acids closely similar to those of polymers incorporating proteins, but different from those of polymers incorporating amino acids: (1) fractionation of humic acids and synthetic polymers by 'Sephadex' gel filtration showed that the percentage of components of molecular weights nominally greater than 100 000 ranged from 52-76 % for eight humic acids tested, 53-59 % for benzoquinone-protein polymers (excluding polymers containing protamine), but less than 20% for all other polymers; (2) acid hydrolysis with 6M HCl resulted in a partial release of polymer nitrogen. Amino acid nitrogen in the hydrolysates accounted for 32.4-51.9 % of humic acid nitrogen, 31.2-56.3 % of the nitrogen of polymers incorporating protein, but less than 10.8% of the nitrogen of polymers incorporating individual amino acids. Experiments with model monomeric N-phenylglycine derivatives and with polymers incorporating simple peptides showed that the bond between the carbon atom of an aromatic ring and the nitrogen atom of an a-amino acid is far more stable to acid hydrolysis than peptide bonds or bonds linking amino acids in humic acids. Glycine is, however, readily released from N-phenylglycine derivatives when conditions favour their oxidation to a quinone-imine intermediate. Incorporation of proteins into phenolic polymers prevented the detection of peptide bonds by the Folin reagent.

scholarly journals Purification and properties of α-galactosidases from Vicia faba seeds

1969 ◽  
Vol 113 (1) ◽  
pp. 49-55 ◽  
Author(s):  
P. M. Dey ◽  
J. B. Pridham
Keyword(s):  
Amino Acid ◽  
Vicia Faba ◽  
Aromatic Amino Acid ◽  
Gel Filtration ◽  
Disc Electrophoresis ◽  
Thermal Stabilities ◽  
Molecular Weights ◽  
Purification And Properties ◽  
Enzyme I ◽  
Carbohydrate Contents

Two forms of α-galactosidase, I and II, exist in Vicia faba seeds and these have been purified 3660- and 337-fold respectively. They behaved as homogeneous preparations when examined by ultracentrifugation, disc electrophoresis and gel filtration. The apparent molecular weights of enzymes I and II, as determined by gel filtration, were 209000 and 38000 respectively. The carbohydrate contents of enzymes I and II were 25% and 2·8% respectively, and the enzymes differed in their aromatic amino acid compositions. Enzyme I was split into six inactive subunits in the presence of 6m-urea. α-Galactosidases I and II showed different pH optima and Km and Vmax. values with p-nitrophenyl α-d-galactoside and raffinose as substrates, and also differed in their thermal stabilities.

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