STRUCTURE OF A GALACTURONAN FROM SUNFLOWER PECTIC ACID

1966 ◽  
Vol 44 (11) ◽  
pp. 1275-1282 ◽  
Author(s):  
V. Zitko ◽  
C. T. Bishop
Keyword(s):  
Galacturonic Acid ◽  
Periodate Oxidation ◽  
Degree Of Polymerization ◽  
Critical Assessment ◽  
Molar Ratio ◽  
Aqueous Methanol ◽  
Pectic Acid ◽  
Potassium Borohydride ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

Fractions of sunflower pectic acid containing 89.8%, 94.2%, and 91.4% of D-galacturonic acid were carboxyl reduced as their methyl or ethylene glycol esters by potassium borohydride. Critical assessment of the effects of three different solvents (water, 80% aqueous dimethyl sulfoxide, and 80% aqueous methanol) on the efficiency of reduction showed that the latter solvent was best. The reductions caused a decrease in the degree of polymerization from 270 to 21. Measurement of the rates of hydrolysis of partially reduced pectic acids containing 90%, 41.6%, 19.9%, 11.0%, and 0.65% of D-galacturonic acid showed that the rate of hydrolysis was directly related to the proportion of galacturonosidic linkages present. Methylation and hydrolysis of the carboxyl-reduced pectic acid fractions yielded 2,3,4,6-tetra-O-methyl-D-galactose and 2,3,6-tri-O-methyl-D-galactose in an approximate molar ratio of 1:20. Results of the periodate oxidation of the carboxyl-reduced pectic acid supported the conclusion inferred from the methylation results that the pectic acid was a linear polymer of 1 → 4 linked α-D-galacturonic acid units.

THE STRUCTURE OF A SYNTHETIC GLUCAN: I. GENERAL STRUCTURAL FEATURES

1962 ◽  
Vol 40 (6) ◽  
pp. 1196-1200 ◽  
Author(s):  
G. G. S. Dutton ◽  
A. M. Unrau
Keyword(s):  
Petroleum Ether ◽  
Acid Hydrolysis ◽  
Direct Evidence ◽  
Periodate Oxidation ◽  
Structural Features ◽  
Degree Of Polymerization ◽  
Molar Ratio ◽  
Partial Hydrolysis ◽  
Large Numbers ◽  
Hydrolysis Of

Only D-glucose was obtained on acid hydrolysis of the glucan. Periodate oxidation released formaldehyde, which was believed to arise from C6 of D-glucofuranose units. From the additional formaldehyde liberated from the borohydride-reduced glucan the degree of polymerization was estimated to be about 165. Complete hydrolysis of the derived polyalcohol gave glycerol, erythritol, D-glucose, and D-xylose. Partial hydrolysis gave glycerol, erythritol, and at least seven non-reducing oligosaccharides. Direct evidence for the existence of relatively large numbers of 1 → 6 and 1 → 4 linkages was found, together with smaller numbers of 1 → 2 linkages. The methylated glucan was freely soluble in chloroform – petroleum ether (5:95), and hydrolysis gave tetra, tri, di, and mono-O-methyl-D-glucoses in a 6:6:3:1 molar ratio.

scholarly journals CONSTITUTION OF A GLUCOMANNAN FROM THE SAPWOOD OF SUGAR MAPLE (ACER SACCHARUM)

1961 ◽  
Vol 39 (12) ◽  
pp. 2423-2430 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Periodate Oxidation ◽  
Linear Structure ◽  
Degree Of Polymerization ◽  
Molar Ratio ◽  
Hydrolysis Of

A glucomannan containing D-mannose and D-glucose in a molar ratio of 7:3 has been isolated from sugar maple sapwood. Electrophorectic examination in acetate and borate buffers showed that the polysaccharide was essentially homogeneous. Methylation and hydrolysis of the glucomannan yielded the following O-methyl ethers:2,3,4,6-tetra-O-methyl-D-glucose (1.1%),2,3,4,6-tetra-O-methyl-D-mannose (2.3%),2,3,6-tri-O-methyl-D-glucose (23.4%),2,3,6-tri-O-methyl-D-mannose (65.9%),2,3-di-O-methyl-D-glucose (2.6%),2,3-di-O-methyl-D-mannose (2.7%).These data in conjunction with periodate oxidation results and estimates of the degree of polymerization indicated that the glucomannan was composed of 25–27 hexose units linked β(1 → 4) in a linear structure. The chains were terminated predominately by D-mannose units; traces of D-xylose were present in terminal positions only and appeared to be part of the glucomannan molecule.

scholarly journals Hydrolysis of Adenosine Triphosphate by Crystalline Yeast Pyrophosphatase

1962 ◽  
Vol 45 (4) ◽  
pp. 31-46 ◽  
Author(s):  
M. Kunitz
Keyword(s):  
Ion Exchange ◽  
Protein Molecule ◽  
Molar Ratio ◽  
Inorganic Pyrophosphatase ◽  
Inorganic Pyrophosphate ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Zn Ions ◽  
Dowex 1

Schlesinger and Coon's report that crystalline yeast inorganic pyrophosphatase, in addition to its known ability to hydrolyze inorganic pyrophosphate in the presence of Mg ions, is also able to catalyze the hydrolysis of ATP and ADP in the presence of Zn ions was confirmed. A systematic study showed that the ratio of 370 of PPase-Mg over ATPase-Zn activities per milligram protein in various preparations of pyrophosphatase obtained in the course of isolation of crystalline pyrophosphatase from baker's yeast was nearly identical in all the preparations, independent of their purity. The course of hydrolysis of ATP by crystalline pyrophosphatase in the presence of Zn was carried out with the aid of ion exchange on Dowex 1. The finding of Schlesinger and Coon that the hydrolysis proceeds from ATP to ADP and then slowly to AMP was confirmed. The kinetics of the first phase of the reaction was found to depend on the molar ratio of Zn/ATP in the reaction mixture. Mg ions in the presence of Zn ions have an accelerating effect on the rate of hydrolysis of ATP. This suggests strongly that both activities—ATPase and PPase—are manifestations of the same active group in the protein molecule of crystalline pyrophosphatase.

THE WATER-SOLUBLE POLYSACCHARIDES OF DERMATOPHYTES: II. A GLUCAN FROM MICROSPORUM QUINCKEANUM

1963 ◽  
Vol 41 (10) ◽  
pp. 2621-2627 ◽  
Author(s):  
H. Alfes ◽  
C. T. Bishop ◽  
F. Blank
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Minimum Degree ◽  
Relative Number ◽  
Degree Of Polymerization ◽  
Water Soluble ◽  
Molar Ratio ◽  
Branch Points ◽  
Degree Of Branching ◽  
Hydrolysis Of

A levorotatory glucan with a minimum degree of polymerization of 36 has been isolated from the water-soluble polysaccharides of the dermatophyte Microsporum quinckeanum. Hydrolysis of the methylated glucan yielded the following O-methyl-D-glucoses: 2,3,4,6-tetra-(10.2 mole%); 2,3,4-tri- (57.7 mole%); 2,4,6-tri- (22.2 mole%); 2,4-di- (8.2 mole%); and 2-mono- (1.6 mole%). The glucan consumed 1.53 moles of periodate with production of 0.70 mole of formic acid per mole anhydroglucose. Reduction and hydrolysis of the periodate-oxidized glucan yielded glycerol, erythritol, and D-glucose in a molar ratio of 72.3:0.6:27.1. The results showed that the glucan consisted of β-D-glucopyranose units joined in straight chains by 1 → 6 (57%) and 1 → 3 (24%) linkages. Approximately 3 in every 37 glucose residues constitute branch points in the glucan with branches occurring at the C6 and C3 positions of the same glucose unit. The glucan bears some resemblance to the yeast glucans of Saccharomyces cerevisiae and Candida albicans but differs from them in the relative number of 1 → 6 and 1 → 3 linkages and in the degree of branching.

CONSTITUTION OF A WATER SOLUBLE HEMICELLULOSE FROM AMERICAN BEECHWOOD (FAGUS GRANDIFOLIA)

1957 ◽  
Vol 35 (6) ◽  
pp. 556-564 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Average Molecular Weight ◽  
Periodate Oxidation ◽  
Reducing Power ◽  
Fagus Grandifolia ◽  
Water Soluble ◽  
Hot Water ◽  
Molar Ratio ◽  
Weight Average Molecular Weight ◽  
Homogeneous Fraction ◽  
Hydrolysis Of

Extraction of beechwood chlorite holocellulose with hot water yielded a hemicellulose in 13.4% yield (based on original extractive-free wood) containing D-xylose 72%, D-galactose 11.0%, and uronic acid 13.2%. Purification of the crude hemicellulose by complexing with Fehling's solution yielded a chemically homogeneous fraction containing D-xylose 83% and 4-O-methyl-D-glucuronic acid 15.5%. Hydrolysis of the fully methylated hemicellulose yielded 2,3,4-tri-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 3-O-methyl-D-xylose, and 3-O-methyl-2-O-(2,3,4-tri-O-methyl-D-glucopyranosyluronic acid)-D-xylose in a molar ratio of 2:35:3:5. On the basis of the methylation data, periodate oxidation, reducing power determinations, and weight average molecular weight values a possible structure for the hemicellulose is proposed.

CONSTITUTION OF AN ARABOGALACTAN FROM JACK PINE (PINUS BANKSIANA LAMB)

1957 ◽  
Vol 35 (9) ◽  
pp. 1010-1019 ◽  
Author(s):  
C. T. Bishop
Keyword(s):  
Methyl Ether ◽  
Pinus Banksiana ◽  
Jack Pine ◽  
Degree Of Polymerization ◽  
Average Degree ◽  
Water Soluble ◽  
Molar Ratio ◽  
Hydrolysis Of ◽  
Homogeneous Hydrolysis

A water soluble arabogalactan isolated from jack pine was shown to have a molar ratio of arabinose to galactose of 1:13, and a number average degree of polymerization of 53 ± 3. Fractionation data and electrophoresis indicated that the arabogalactan was homogeneous. Hydrolysis of the methyl ether of the polysaccharide yielded 2,3,5-tri-O-methyl-L-arabinose (4 moles); 2,3,4,6-tetra-O-methyl-D-galactose (12–13 moles); 2,3,4-tri-O-methyl-D-galactose (19 moles); 2,6-di-O-methyl-D-galactose (1 mole); and 2,4-di-O-methyl-D-galactose (14 moles). Some features of the structure of the arabogalactan are discussed on the basis of these results.

THE STRUCTURAL ANALYSIS OF SOME ACIDIC XYLANS BY PERIODATE OXIDATION

1962 ◽  
Vol 40 (2) ◽  
pp. 348-352 ◽  
Author(s):  
G. G. S. Dutton ◽  
A. M. Unrau
Keyword(s):  
Acid Hydrolysis ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Small Degree ◽  
Degree Of Polymerization ◽  
Borohydride Reduction ◽  
Mild Acid Hydrolysis ◽  
Degree Of Branching ◽  
Hydrolysis Of ◽  
Mild Acid

By determining the amount of formaldehyde produced on periodate oxidation of borohydride-reduced apple- and cherry-wood xylans the degree of polymerization was shown to be 155 and 100 respectively. Acid hydrolysis of the polyols obtained by periodate oxidation and borohydride reduction gave ethylene glycol in amounts indicating that these xylans have a small degree of branching. Mild acid hydrolysis of the polyols demonstrated that in these xylans D-glucuronic acid as well as 4-O-methyl-D-glucuronic acid was present and that some of the former occupied non-terminal positions.

CONSTITUTION OF A HEMICELLULOSE FROM WHEAT BRAN

1955 ◽  
Vol 33 (1) ◽  
pp. 56-67 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Oxalic Acid ◽  
Wheat Bran ◽  
Uronic Acid ◽  
Periodate Oxidation ◽  
Reducing Power ◽  
Degree Of Polymerization ◽  
Alkaline Extraction ◽  
Acidic Polysaccharide ◽  
Simultaneous Production ◽  
Hydrolysis Of

The hemicellulose prepared from wheat bran by alkaline extraction was an acidic polysaccharide containing arabinose (50.0%), xylose (38.5%), and uronic acid (9.0%). Graded hydrolysis with 0.02 N oxalic acid preferentially released 65% of the arabinose with only a small simultaneous production of xylose. Hydrolysis of the full methylated hemicellulose yielded 2,3,4-tri-O-methyl-, 2,3-di-O-methyl-, 2-O-methyl-, and free D-xylose; 2,3,5-tri-O-methyl-, 2,5-di-O-methyl-, and probably 3- and 5-O-methyl-L-arabinose. These data, together with those from periodate oxidation, strongly suggested that the molecule was a highly branched araboxylan. Viscosity measurements and reducing power determinations indicated a degree of polymerization of 300.

Hydrolysis of 2-acyl-sn-glycero-3-phosphocholines in guinea pig heart mitochondria

1990 ◽  
Vol 68 (9) ◽  
pp. 1090-1095
Author(s):  
Ketan Badiani ◽  
Leona Page ◽  
Gilbert Arthur
Keyword(s):  
Fatty Acids ◽  
Guinea Pig ◽  
Molecular Species ◽  
Unsaturated Fatty Acids ◽  
Heart Mitochondria ◽  
Molar Ratio ◽  
Guinea Pig Heart ◽  
Rate Of Hydrolysis ◽  
The Individual ◽  
Hydrolysis Of

Although both 2-acyl-sn-glycero-3-phosphocholine and 1-acyl-sn-glycero-3-phosphocholine may be produced from phosphatidylcholine hydrolysis, studies on the former have lagged behind that of the latter. In this study a lysophospholipase A2 that hydrolyses 2-acyl-sn-glycero-3-phosphocholine has been characterized in guinea pig heart mitochondria. The lysophospholipase A2 activity was not dependent on Ca2+ and was inhibited differentially by saturated and unsaturated fatty acids. This lysophospholipase A2 activity was able to discriminate among different molecular species of 2-acyl-sn-glycero-3-phosphocholines when they were presented individually or in pairs. The order of decreasing rates of hydrolysis of different molecular species of 2-lysophosphatidylcholines, when the substrates were presented singly, was 18:2 > 20:4 > 18:1 > 16:0. A differential inhibition of the rate of hydrolysis of the individual substrates was observed when the substrates were presented in pairs. The degree of inhibition was dependent on the molar ratio of the mixed substrates. The characteristics of the enzyme suggest that involvement in the selective release of fatty acids from mitochondrial phosphatidylcholine would depend on a high selectivity of phospholipase A1 for different molecular species of phosphatidylcholine. A lysophospholipase A1 activity was also characterized in the mitochondria with a distinct acyl specificity from the lysophospholipase A2. Other characteristics of the two lysophospholipases suggest that the two reactions are not catalysed by the same enzyme.Key words: lysophospholipases, mitochondria, fatty acid relase, heart.

THE STRUCTURE OF LINSEED MUCILAGE: PART II

1962 ◽  
Vol 40 (7) ◽  
pp. 1266-1279 ◽  
Author(s):  
K. Hunt ◽  
J. K. N. Jones
Keyword(s):  
Galacturonic Acid ◽  
Main Chain ◽  
Periodate Oxidation ◽  
Neutral Fraction ◽  
Acetate Solution ◽  
Partial Acid Hydrolysis ◽  
Cupric Acetate ◽  
Acidic Fraction ◽  
Degraded Material ◽  
Hydrolysis Of

Linseed mucilage has been separated into an acidic and a neutral fraction. The acidic fraction was further separated, by the use of cupric acetate solution, into two fractions, CuI and CuII. Fraction CuI contained L-rhamnose, L-galactose, and D-galacturonic acid. The methylated reduced polysaccharide gave on hydrolysis 2,3,4-tri-O-methyl-L-rhamnose, 3,4-di-O-methyl-L-rhamnose, 4-O-methyl-L-rhamnose, 2,3,4,6-tetra-O-methyl-D-galactose, 2,3,6-tri-O-methyl-D-galactose, and 2,3-di-O-methyl-D-galactose (?); L-galactose was lost during the methylation process. Periodate oxidation studies on the material indicated that the polymer was composed of a main chain of L-rhamnose units with most of the L-galactose units attached as non-reducing end groups. Fraction CuII contained L-rhamnose, L-fucose, L-galactose, and D-galacturonic acid. The methylated reduced polysaccharide gave on hydrolysis 2,3,4-tri-O-methyl-L-fucose, 2,3,4,6-tetra-O-methyl-L-galactose, 2,3,6-tri-O-methyl-D-galactose, 4-O-methyl-L-rhamnose, L-rhamnose, and possibly 2,3-di-O-methyl-D-galactose and 3-O-methyl-D-galactose. Periodate oxidation studies and a degradation by the Smith procedure indicated the presence of a L-rhamnose backbone with L-fucose and L-galactose units attached as non-reducing end groups.The neutral fraction yielded a periodate-oxidizable material after one Smith-type degradation. Periodate oxidation studies indicated that the degraded material was branched. Methylation of the degraded polysaccharide followed by hydrolysis yielded 2,3,4-tri-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,4-di-O-methyl-D-xylose, 4-O-methyl-D-xylose, D-xylose, and traces of 2,3,4-trt-O-methyl- or 2,5-di-O-methyl-L-arabinose, 2,4-di-O-methyl-D-xylose, and 3-O-methyl-D-xylose. The main backbone of the degraded polysaccharide appeared to consist of (1 → 4)-linked D-xylose units. Linkages of the (1 → 3) type were also present. The smaller fragments from the Smith-type degradation, L-arabinose, 2-O-α-L-arabinosyl glycerol, and glycerol were characterized. A partial acid hydrolysis of the neutral fraction yielded a number of oligosaccharides.

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