Protective action of phosphorylcholine on mitochondrial oxidative phosphorylation

Róssi, Carlo; Rossi, C.S.; Sartorelli, L.; Siliprandi, D.; Siliprandi, N.

doi:10.1016/0003-9861(62)90003-6

Cited by 10 publications

(4 citation statements)

References 17 publications

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“…The partial stabilizing effect of lecithin (Table 3) suggests that some degree of stabilization can be achieved by adding an alternative lipase substrate. Lecithin is thought not to inhibit lipase activity but to divert the activity of these enzymes away from the cell membranes (18). Treatment of cell extracts with PMSF is probably another example of direct inhibition of lipase activity, given that PMSF is known to inhibit lipases (16), in addition to having a more traditionally recognized role as a protease inhibitor.…”

Section: Discussionmentioning

confidence: 99%

“…However, leupeptin did not stabilize ammoniadependent O 2 uptake activity (not shown). Lecithin was reported to stabilize mitochondrial activities by protecting membranes from lipolysis by providing an alternative substrate for phospholipases (18). Ammonia-dependent O 2 uptake activity was stabilized by egg yolk lecithin (10 mg/ml); however, lecithin was less effective than BSA, CuCl 2 , or PMSF (Table 3).…”

Section: Vol 177 1995 Stabilization Of Ammonia-oxidizing Activity 4911mentioning

confidence: 99%

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Roles of bovine serum albumin and copper in the assay and stability of ammonia monooxygenase activity in vitro

1995

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We investigated the effects of bovine serum albumin (BSA) on both the assay and the stability of ammoniaoxidizing activity in cell extracts of Nitrosomonas europaea. Ammonia-dependent O 2 uptake activity of freshly prepared extracts did not require BSA. However, a dependence on BSA developed in extracts within a short time. The role of BSA in the assay of ammonia-oxidizing activity apparently is to absorb endogenous free fatty acids which are present in the extracts, because (i) only proteins which bind fatty acids, e.g., BSA or ␤-lactoglobulin, supported ammonia-oxidizing activity; (ii) exogenous palmitoleic acid completely inhibited ammonia-dependent O 2 uptake activity; (iii) the inhibition caused by palmitoleic acid was reversed only by proteins which bind fatty acids; and (iv) the concentration of endogenous free palmitoleic acid increased during aging of cell extracts. Additionally, the presence of BSA (10 mg/ml) or CuCl 2 (500 M) stabilized ammoniadependent O 2 uptake activity for 2 to 3 days at 4؇C. The stabilizing effect of BSA or CuCl 2 was apparently due to an inhibition of lipolysis, because both additives inhibited the increase in concentrations of free palmitoleic acid in aging extracts. Other additives which are known to modify lipase activity were also found to stabilize ammonia-oxidizing activity. These additives included HgCl 2 , lecithin, and phenylmethylsulfonyl fluoride.

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Section: Discussionmentioning

confidence: 99%

Section: Vol 177 1995 Stabilization Of Ammonia-oxidizing Activity 4911mentioning

confidence: 99%

Roles of bovine serum albumin and copper in the assay and stability of ammonia monooxygenase activity in vitro

1995

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“…The importance of mitochondrial phospholipids in the established (15). Nygaard and Sumner (20) explained the inactivation of succinoxidase by venom in terms of the hydrolysis of lecithin which they suggested might be a component linking succinic dehydrogenase with cytochrome c. The fall in P/O ratio following a venom addition has been explained primarily as due to loss of phospholipid (23,25). While not excluding the possibility that the phospholipase A-induced swelling of Phaseolus mitochondria is a result of hydrolysis of membrane phospholipids per se leading to an increase in membrane permeability (14), the data of Table I and Figure 1 suggest that this mechanism is unlikely.…”

Section: Resultsmentioning

confidence: 99%

“…Phospholipase A has been shown to inhibit NADH oxidase, succinate-and NADH-cytochrome c reductase (28) and succinoxidase activities (13). Several workers have shown a decrease in the P/O ratio of isolated mitochondria as a result of phospholipase A action in vitro (23,25) and also in vivo (2).…”

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Swelling of Phaseolus Mitochondria Induced by the Action of Phospholipase A

Earnshaw¹,

Truelove²

1970

Plant Physiol.

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Phaseolus vulgaris mitochondria incubated in sucrose swell rapidly upon the addition of phospholipase A. Bovine serum albumin inhibits the swelling. The release of free fatty acids as a result of phospholipase A action on the mitochondria is detected only in the presence of bovine serum albumin, which promotes the hydrolysis of both mitochondrial phospholipids and purified lecithin. Either free fatty acid or lysolecithin is able to initiate an extensive mitochondrial swelling in sucrose. It is suggested that phospholipase A-induced swelling results from the release of lysophosphatides plus free fatty acids and their subsequent detergent action on the membranes rather than phospholipid loss per se.Phospholipase A (phosphatide acyl-hydrolase, EC 3.1.1.4) of snake venom catalyzes the hydrolysis of diacylated nitrogencontaining phosphoglycerides with the liberation of the fatty acid esterified at the ,3-position and formation of the lysophosphoglyceride. The metabolic results of adding snake venom or a phospholipase A preparation to animal mitochondria are well documented. Petrushka et al. (22) observed, following the addition of heated snake venom to rat mitochondria, an initial stimulation of the respiratory rate followed by a rapid inhibition. Phospholipase A has been shown to inhibit NADH oxidase, succinate-and NADH-cytochrome c reductase (28) and succinoxidase activities (13). Several workers have shown a decrease in the P/O ratio of isolated mitochondria as a result of phospholipase A action in vitro (23, 25) and also in vivo (2).In addition to the effects of phospholipase A on metabolism, there are several reports indicating that structural disorganization also occurs. The treatment of an NADH oxidase preparation resulted in extensive solubilization of the NADH dehydrogenase activity (24), and cytochrome c release occurred upon incubation of electron transport particles with phospholipase A (1). lipase A to provide a clear separation of the inner and outer membrane systems of beef heart mitochondria. It has also been reported that the addition of venom to rat liver mitochondria produced a marked swelling response (26).As part of a detailed study of volume changes exhibited by Phaseolus mitochondria (11, 12), it was of interest to determine whether phospholipase A was able to induce swelling in plant mitochondria as well as in animal. Phaseolus mitochondria show rapid spontaneous swelling in tris-buffered KC1 in a process strongly inhibited by bovine serum albumin but do not swell appreciably in tris-buffered sucrose (12). We wished to determine whether phospholipsase A would induce swelling in sucrose and whether BSA4 affected the system. MATERIALS AND METHODSIsolation ofMitochondria. Seed of dwarf French bean, Phaseolus vulgaris (var. Canadian wonder) was sown and germinated as described by Opik and Simon (21). Mitochondria were isolated from the etiolated hypocotyls on the 6th day following planting by a method similar to the procedure of Kenefick and Hanson (17) as described previously (11). Mitoch...

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On Ca++ Transport Across the Mitochondrial Membrane: The Role of the Chemical Nature and Pattern of Mitochondrial Phospholipids

Rossi

Sartorelli

Carafoli

1971

Advances in Experimental Medicine and Biology

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Protective action of phosphorylcholine on mitochondrial oxidative phosphorylation

Cited by 10 publications

References 17 publications

Roles of bovine serum albumin and copper in the assay and stability of ammonia monooxygenase activity in vitro

Roles of bovine serum albumin and copper in the assay and stability of ammonia monooxygenase activity in vitro

Swelling of Phaseolus Mitochondria Induced by the Action of Phospholipase A

On Ca++ Transport Across the Mitochondrial Membrane: The Role of the Chemical Nature and Pattern of Mitochondrial Phospholipids

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