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.

scholarly journals Evidence for the regulation of guinea-pig heart microsomal phosphatidylcholine-hydrolysing phospholipase A1 by guanosine 5′-[γ-thio]triphosphate

1992 ◽  
Vol 288 (3) ◽  
pp. 965-968 ◽  
Author(s):  
K Badiani ◽  
X Lu ◽  
G Arthur
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Guinea Pig ◽  
Molecular Species ◽  
Inhibitory Effect ◽  
Phospholipase A1 ◽  
Guinea Pig Heart ◽  
Substrate Specificities ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

We have recently characterized lysophospholipase A2 activities in guinea-pig heart microsomes and postulated that these enzymes act sequentially with phospholipases A1 to release fatty acids selectively from phosphatidylcholine (PC) and phosphatidylethanolamine, thus providing an alternative route to the phospholipase A2 mode of release. In a further investigation of the postulated pathway, we have characterized the PC-hydrolysing phospholipase A1 in guinea-pig heart microsomes. Our results show that the enzyme may have a preference for substrates with C16:0 over C18:0 at the sn-1 position. In addition, although the enzyme cleaves the sn-1 fatty acid, the rate of hydrolysis of PC substrates with C16:0 at the sn-1 position was influenced by the nature of the fatty acid at the sn-2 position. The order of decreasing preference was C18:2 > C20:4 = C18:1 > C16:0. The hydrolyses of the molecular species were differentially affected by heating at 60 degrees C. An investigation into the effect of nucleotides on the activity of the enzyme showed that guanosine 5′-[gamma-thio]triphosphate (GTP[S]) inhibited the hydrolysis of PC by phospholipase A1 activity, whereas GTP, guanosine 5′-[beta-thio]diphosphate (GDP[S]), GDP, ATP and adenosine 5′-[gamma-thio]triphosphate (ATP[S]) did not affect the activity. The inhibitory effect of GTP[S] on phospholipase A1 activity was blocked by preincubation with GDP[S]. A differential effect of GTP[S] on the hydrolysis of different molecular species was also observed. Taken together, the results of this study suggest the presence of more than one phospholipase A1 in the microsomes with different substrate specificities, which act sequentially with lysophospholipase A2 to release linoleic or arachidonic acid selectively from PC under resting conditions. Upon stimulation and activation of the G-protein, the release of fatty acids would be inhibited.

scholarly journals Lysophospholipase A2 activity in guinea-pig heart microsomal fractions displaying high activities with 2-acylglycerophosphocholines with linoleic and arachidonic acids

1989 ◽  
Vol 261 (2) ◽  
pp. 581-586 ◽  
Author(s):  
G Arthur
Keyword(s):  
Guinea Pig ◽  
Phospholipase A1 ◽  
Guinea Pig Heart ◽  
Mammalian Tissues ◽  
Rate Of Hydrolysis ◽  
The One ◽  
Arachidonic Acids ◽  
High Degree ◽  
Hydrolysis Of ◽  
Lysophospholipase Activity

Lysophospholipases A1 which catalyse the hydrolysis of acyl groups from 1-acylglycerophosphocholine (GPC) have been characterized in a number of mammalian tissues and do not exhibit any acyl specificity. In the present study lysophospholipase activity in guinea-pig heart microsomes (microsomal fractions) that hydrolyses 2-acyl-GPC was detected and characterized. The enzyme showed a high degree of acyl specificity. The relative rates of hydrolysis of individual 2-acyl-GPCs with different fatty acids was as follows: C18:2/C20:1/C18:1/C16:0, 14:6:1:1. When substrates were presented in pairs, the hydrolysis of each substrate by the enzyme was inhibited, but to very different extents. Of each pair of lysolipids examined (2-arachidonoyl- and 2-palmitoyl-GPC; 2-arachidonoyl- and 2-linoleoyl-GPC), the one with the expected higher rate of hydrolysis was more severely inhibited and the degree of inhibition was dependent on the concentration of the other lysolipid. The characteristics of the lysophospholipase A2 suggest the enzyme could work in concert with phospholipase A1 to release arachidonic and linoeic acids for further metabolism. The properties of lysophospholipase A2 and A1 suggest that they are different enzymes.

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.

scholarly journals Comparing the Effects of Different Unsaturated Fatty Acids on Fermentation Performance of Saccharomyces cerevisiae and Aroma Compounds during Red Wine Fermentation

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 538 ◽  
Author(s):  
Pei-Tong Liu ◽  
Chang-Qing Duan ◽  
Guo-Liang Yan
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Decanoic Acid ◽  
Isoamyl Acetate ◽  
Aroma Compounds ◽  
Ethyl Esters ◽  
Yeast Fermentation ◽  
Ethyl Hexanoate ◽  
Low Concentrations ◽  
The Individual

To understand the individual enological function of different unsaturated fatty acids (UFAs), the separated effects of three different UFAs, linoleic acid (LA), oleic acid (OA), and α-linolenic acid (ALA), on yeast fermentation and aroma compounds were investigated in the alcoholic fermentation of Cabernet Sauvignon wine. The results showed that, besides concentration, UFAs types could also influence fermentation process and volatiles in final wine. Low concentrations of UFAs (12 and 60 mg/L), especially LA and OA, significantly promoted fermentation activity and most volatiles when compared to the control, however, the effect became the inhibition with increasing concentrations of UFAs (120 and 240 mg/L). It was interesting to find that OA addition (12 and 60 mg/L) could generate more acetate esters (especially isoamyl acetate) in wine, while 12 mg/L LA facilitated more fatty acids formation (octanoic acid and decanoic acid). In comparison, 120 and 240 mg/L ALA produced more amount of C6 alcohols (1-hexanol) and higher alcohols (isobutyl alcohol and 2,3-butanediol). UFAs additions were unfavorable for ethyl esters formation, except for an increment of ethyl hexanoate in 12 mg/L OA wine. As a result, different aromatic profiles of wines were generated by variations of UFAs types and levels, as shown by PCA. The transcriptional data revealed that the expressions of aroma-related genes, such as BAT1, BAT2, PDC1, PDC5, PDC6, ACC1, FAS1, ATF1, EEB1, and EHT1 were correlated with aroma compounds productions in different treatments. Our data suggested that the three UFAs have different enological functions and they could generate different aromatic profiles. Thus, besides concentrations, it is essential to consider the types of UFAs when applying the strategy to adjust UFAs contents to modulate the aromatic quality of wines.

scholarly journals Inhibition by unsaturated fatty acids of type II secretory phospholipase A2 synthesis in guinea-pig alveolar macrophages

2000 ◽  
Vol 267 (12) ◽  
pp. 3633-3639 ◽  
Author(s):  
Mounia Alaoui El Azher ◽  
Nathalie Havet ◽  
Monique Singer ◽  
Claude Dumarey ◽  
Lhousseine Touqui
Keyword(s):  
Fatty Acids ◽  
Guinea Pig ◽  
Phospholipase A2 ◽  
Alveolar Macrophages ◽  
Unsaturated Fatty Acids ◽  
Type Ii ◽  
Secretory Phospholipase A2 ◽  
Secretory Phospholipase

scholarly journals The catabolism of plasmenylcholine in the guinea pig heart

1986 ◽  
Vol 236 (2) ◽  
pp. 475-480 ◽  
Author(s):  
G Arthur ◽  
L Page ◽  
T Mock ◽  
P C Choy
Keyword(s):  
Guinea Pig ◽  
Phospholipase A2 ◽  
High Specificity ◽  
Experimental Conditions ◽  
Ph Optimum ◽  
Major Pathway ◽  
Guinea Pig Heart ◽  
Mitochondrial Fractions ◽  
Wide Range ◽  
Hydrolysis Of

The hydrolysis of the alkenyl bonds of plasmenylcholine and plasmenylethanolamine by plasmalogenase, followed by hydrolysis of the resultant lysophospholipid by lysophospholipase, has been postulated as the major pathway for the catabolism of these plasmalogens. However, the postulation was based solely on the presence of plasmalogenase activity towards plasmenylethanolamine and plasmenylcholine in the brain. In this study we have demonstrated the absence of plasmalogenase activity for plasmenylcholine in the guinea pig heart under a wide range of experimental conditions. Plasmenylcholine was hydrolysed by phospolipase A2 activities in cardiac microsomal, mitochondrial and cytosolic fractions. Phospholipase A2 activities in these fractions had an alkaline pH optimum and were enhanced by Ca2+. The enzymes also displayed high specificity for plasmenylcholine with linoleoyl or oleoyl at the C-2 position. Lysoplasmalogenase activity for lysoplasmenycholine was also detected and characterized in the microsomal and mitochondrial fractions. Since the cardiac plasmalogenase is only active towards plasmenylethanolamine but not plasmenylcholine, the catabolism of these two plasmalogens must be different from each other. We postulate that the major pathway for the catabolism of plasmenycholine involves the hydrolysis of the C-2 fatty acid by phospholipase A2, and hydrolysis of the vinyl ether group of the resultant lysoplasmenylcholine by lysoplasmalogenase.

Application of Benzyl Ester of Modified Vegetable Oils as Rubber Processing Oils

2011 ◽  
Vol 415-417 ◽  
pp. 1164-1167 ◽  
Author(s):  
Hasleena Boontawee ◽  
Charoen Nakason ◽  
Azizon Kaesaman ◽  
Anoma Thitithammawong ◽  
Sopa Chewchanwuttiwong
Keyword(s):  
Fatty Acids ◽  
Vegetable Oils ◽  
Dynamic Mechanical Properties ◽  
Benzyl Ester ◽  
Molar Ratio ◽  
Mixing Energy ◽  
Rubber Compounds ◽  
Different Types ◽  
Benzyl Esters ◽  
Hydrolysis Of

Benzyl esters of fatty acids based on three types of vegetable oils (i.e., coconut, palm, and soybean oils) were in-house prepared. They were used as alternative rubber processing oil to replace conventional aromatic oil which has been banned by European community since December 2009. Fatty acids were first prepared by hydrolysis of vegetable oils and thereafter esterified with benzyl alcohol in the presence of sulfuric acid as a catalyst. The reaction based on molar ratio of fatty acid:benzyl alcohol:sulfuric acid was set at 1.5:1.0:0.05 gave yield of benzyl esters higher than 80%. Rubber compounds containing different types of benzyl ester were prepared according to the standard formulation of ASTM 3184. It was found that the processing oil in the form of benzyl esters is possible to use instead of aromatic oil in rubber formulation. Various parameters and properties include mixing energy, Mooney viscosity, curing, mechanical and dynamic mechanical properties of rubber compounds and vulcanizates have been investigated.

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.

scholarly journals Mechanisms of hepatic phosphatidylcholine synthesis in the developing guinea pig: contributions of acyl remodelling and of N-methylation of phosphatidylethanolamine

1993 ◽  
Vol 290 (1) ◽  
pp. 67-73 ◽  
Author(s):  
G C Burdge ◽  
F J Kelly ◽  
A D Postle
Keyword(s):  
Fatty Acids ◽  
Guinea Pig ◽  
Molecular Species ◽  
Essential Fatty Acids ◽  
Specific Radioactivity ◽  
Long Chain Fatty Acids ◽  
Radioactivity Analysis ◽  
Species Specific ◽  
Phosphatidylcholine Synthesis

Hepatic phosphatidylcholine (PC) from the immature fetal guinea pig at day 55 of gestation comprised mainly unsaturated molecular species containing C18:2(n-6) and C22:6(n-3) at the sn-2 position, reflecting placental permeability to essential fatty acids. At both day 55 and term (day 68), [Me-14C]choline was incorporated in utero over 3 h largely into sn-1-C16:0 PC species, with incorporation into sn-1-C18:0 PC species increasing by 18 h of incubation. Comparison of specific radioactivities after 3 h and 18 h suggests PC acyl remodelling by phospholipase A1. No incorporation into C20:4(n-6)-containing PC species could be detected of either [Me-14C]choline in vivo or CDP-[Me-14C]choline in isolated microsomes. The major phosphatidylethanolamine (PE) species were 16:0/22:6 and 18:0/22:6. Although [14C]ethanolamine was initially incorporated mainly into sn-1-C16:0 species, specific-radioactivity analysis suggested differential turnover rather than acyl remodelling. [1,2-14C]Ethanolamine and [Me-14C]methionine incorporation into PC molecular species indicated that both newly synthesized and total PE pools were available for N-methylation. Since the PC pool synthesized from PE included C20:4- and C22:6-containing species, N-methylation may provide a mechanism for supplying essential long-chain fatty acids to developing tissues that can be regulated independently from bulk PC synthesis.

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