Some properties of the actomyosin-like protein of the uterus

Needham, Dorothy M.; Cawkwell, J. M.

doi:10.1042/bj0630337

Cited by 63 publications

(11 citation statements)

References 21 publications

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“…Preparation of the purified actomyosin. The early stages were similar to those described by Needham & Cawkwell (1956), except that when small quantities of tissue were used (20-30 g.) it was disintegrated at 40 by thorough grinding with acid-washed sand or quartz, the extracting fluid being added gradually. This had the advantage over the use of the Waring Blendor that frothing was avoided.…”

Section: Materia8mentioning

confidence: 76%

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Some properties of uterus actomyosin and myofilaments

Needham

Williams

1959

Biochemical Journal

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Some properties of the actomyosin-like adenosine triphosphatase of the uterus have already been described (see Needham & Cawkwell, 1956). It was shown that this enzyme splits off only one phosphate group and has a pH-activity curve in 05Mpotassium chloride resembling that of myosin from skeletal muscle. The activity, however, is much lower than that of skeletal-muscle actomyosin; rabbit-and pig-uterus actomyosin (with which most of this work was done) also differ from skeletal muscle actomyosin (which is somewhat inhibited at higher concentrations of potassium chloride) in being less active in media containing 0-1 Mpotassium chloride than in those containing 05Mpotassium chloride. Thus at 280, with Ca2+ ion activation, the values for pmoles of inorganic phosphorus liberated/mg. of nitrogen/min. are about 0-2 and 0-6 in media containing 0.1 and

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Section: Materia8mentioning

confidence: 76%

“…Cell-particle suspension. This was made as described by Needham & Cawkwell (1956). The residues obtained after centrifuging the 0-5M-KCI extract at 100 000 g always 1.…”

Section: Materia8mentioning

confidence: 99%

Some properties of uterus actomyosin and myofilaments

Needham

Williams

1959

Biochemical Journal

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“…However, when added together the combination thus formed was sensitive, indicating that a thrombosthenin complex, analogous to muscle actomyosin, had formed. However, the ATPase activity of the thrombosthenin complex has been found to be 50 to 100 times below the values for muscle actomyosin (Hasselbach 1951) and 5-10 times lower than the values for the contractile protein of smooth muscle reported by Needham & Cawkwell (1956). Thrombosthenin differs also from muscle actomyosin in its immunological properties.…”

Section: Behnkementioning

confidence: 66%

Morphological Changes in the Hyalomere of Rat Blood Platelets in Experimental Venous Thrombi

Behnke

1966

Scandinavian Journal of Haematology

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The fine structure of rat blood platelets aggregated in experimentally produced thrombi was examined by light‐ and electron microscopy after glutaraldehyde fixation. In the ‘body’ regions of the thrombi two kinds of platelet aggregates, arranged in irregular but distinct zones, could be distinguished. In one of the zones platelets were totally degranulated and appeared as nearly empty sacs. In the other zone degranulation was less extensive, and fine, approximately 50 Å thick filaments were a prominent feature of the hyaloplasm. Microtubules were present in the hyaloplasm of platelets in both zones. The filaments and the microtubules are suggested as possible morphological substrates of the contractile proteins known to be present in platelets.

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“…Kielley & Meyerhof (1950) found the magnesium activated ATP-ase of muscle was inactivated by a phospholipase C preparation from Clostridium welchii, the splitting of phospholipid being proportional to the inactivation. On the other hand, the myosin ATP-ase appears to be unaffected (Macfarlane, 1950) and similarly a particulate ATP-ase prepared from rat uterus was found to be resistant to phospholipase attack (Needham & Cawkwell, 1956). Swanson & Mitchell (1952) have isolated a highly purified preparation of ATP-ase from liver nuclei which was especially rich in phospholipids (reported by Artom, Lehninger (1956) have found approximately 20% of phospholipid in a particulate fraction isolated from mitochondria which was able to carry out oxidative phosphorylation during the oxidation of /?-hydroxybutyric acid.…”

Section: (2) Structural Roles Especially In Cell Oxidasesmentioning

confidence: 99%

THE ANIMAL PHOSPHOLIPIDS: THEIR STRUCTURE, METABOLISM and BIOLOGICAL SIGNIFICANCE

Dawson

1957

Biological Reviews

135

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SUMMARY Phospholipids are universally present in all mammalian tissues and in all parts of the cell, including the mitochondria, microsomes and nucleus. They appear often to be attached to the tissue proteins by some unknown type of bonding. The use of physical methods of fractionation to separate crude lipids extracted from tissues has resulted in the discovery of a number of new phospholipids apart from lecithin, cephalin and sphingomyelin, notably phosphatidylserine, phosphatidylinositol and diphosphoinositide. As isolated, the phosphoglycerides all have the a structure and the L configuration. Evidence is accumulating that individual animal tissues can synthesize their complete requirements of new phospholipids without resource to other organs. In all tissues, even in the adult animal, the phospholipids are continually being broken down and resynthesized at the same rate, so that under normal physiological conditions a constant concentration is maintained. The mechanism of phospholipid biosynthesis has only been ascertained up to now for the phosphoglycerides: lecithin and phosphatidylethanolamine. With these compounds a phosphorylated base molecule (phosphorylcholine or phosphoryl‐ethanolamine) first reacts with cytidine triphosphate, forming an activated complex, cytidine diphosphate ‘base’. This then combines with a diglyceride molecule, forming the phosphoglyceride, and splitting off cytidine monophosphate. It is possible that the diglyceride needed by the system is formed by the dephosphoryla‐tion of phosphatidic acid, a lipid which is enzymically synthesized in tissues from α‐glycerophosphoric acid and two coenzyme A‐activated fatty acids. One route for the catabolism of lecithin and phosphatidylethanolamine appears to be through the lysophosphoglycerides and glycerophosphorylated bases. The glycerophosphate finally formed can either be used for phosphoglyceride resynthesis or it can enter the glycolytic system of the tissue. Certain isotopic evidence suggests that, as well as this catabolic process, the phosphorylated base ‘units’ may turnover independently and more rapidly than the glyceride part of the phospholipid molecule. Possibly the recent and unconfirmed demonstration of a phospholipase C, which forms phosphorylcholine from lecithin, may be connected with this process. The rate at which individual phospholipids turnover in various organs has still to be ascertained. Many previous estimates are unsatisfactory because inadequate experimental results have been applied to theoretically derived formulae expressing turnover rates. For similar reasons it is often extremely difficult to interpret reported changes in the incorporation rate of isotopes into phospholipids during physiological activity. No definite metabolic role can yet be ascribed to phospholipids which would account for their rapid turnover in tissues. The evidence is against their being obligatory intermediates, either in the resynthesis of triglycerides during fat digestion or in the oxidation of neutral fat. Neither do they appear ...

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Some properties of the actomyosin-like protein of the uterus

Cited by 63 publications

References 21 publications

Some properties of uterus actomyosin and myofilaments

Some properties of uterus actomyosin and myofilaments

Morphological Changes in the Hyalomere of Rat Blood Platelets in Experimental Venous Thrombi

THE ANIMAL PHOSPHOLIPIDS: THEIR STRUCTURE, METABOLISM and BIOLOGICAL SIGNIFICANCE

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