Influence of dye binding on the sensitized photooxidation of amino acids

Bellin, Judith S.; Yankus, C.A.

doi:10.1016/0003-9861(68)90099-4

Cited by 85 publications

(38 citation statements)

References 23 publications

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“…Activity also remained after treatment with diacetyl trimer (30). Treatment with o-phthalaldehyde (31) as well as photooxidation (32) of the toxin resulted in a complete loss of the toxic activity. A fluorodinitrobenzene derivative of the toxin could not be investigated due to its apparent insolubility.…”

mentioning

confidence: 91%

Investigations into the relationship between structure and function of diphtheria toxin.

Everse¹,

Lappi²,

Beglau³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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Studies on the structure-function relationship of diphtheria toxin are reported. New methods are described for the preparation of pure intact ("unnicked") molecule (or the A chain) to enter the cell (11). The complete amino acid sequence of the A chain has recently become available (12). A recent report by Iglewski and Rittenberg (13) indicated that protein synthesis in Ehrlich-Lettr6 ascites carcinoma cells is much more sensitive to the action of diphtheria toxin than that in normal mouse spleen cells, and that Ehrlich-Lettre tumors regressed in mice following an injection of the affected mice with diphtheria toxin. A difference in sensitivity to diphtheria toxin was also found in human breast carcinoma cells as compared to normal human cells. These observations suggest that diphtheria toxin may prove to be a useful anti-cancer agent, although more recent data indicate that the difference in sensitivity of tumor cells to toxin as compared to normal cells may not be as large as originally thought (14,15).It is therefore of considerable interest to us to investigate the mechanism of action of diphtheria toxin in greater detail. More specifically, we are trying to gain further information concerning the amino acid residues of the toxin that are essential for its activity, and to investigate the mechanism by which diphtheria toxin enters the cell. Some of the results obtained during this investigation are presented in this paper. MATERIALS AND METHODS Materials

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mentioning

confidence: 91%

Investigations into the relationship between structure and function of diphtheria toxin.

Everse¹,

Lappi²,

Beglau³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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“…There exists an extensive literature detailing similar dye-sensitized reactions (6,(10)(11)(12)(13)(14)(15); most experiments were carried out batchwise in Warburg apparatus. Nevertheless, this literature provides a base for development of new analytical methods employing dye-sensitized photochemical reactions carried out in flowing streams.…”

mentioning

confidence: 99%

Dye-sensitized continuous photochemical analysis. Identification and relative importance of key experimental parameters

White¹,

Fitzgerald²

1975

Anal. Chem.

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Important operating conditions for a new analytical technique, based on dye-sensitized reactions carried out in flowing streams, are evaluated. The photoredox reaction used is a form of triplet energy transfer wherein a colored organic dye absorbs light to generate the excited state triplet, which then abstracts electrons from a suitable substrate. The products of the reaction are colorless reduced dye and substrate oxidation products; spectrophotometric measurement of dye photobleaching is employed. The rate and stoichiometry of photoredox reactions are dramatically affected by the structures of dye and substrate used, dissolved oxygen, and reaction pH. Other important parameters, largely associated with the apparatus used, are dyecarrier flow rate, photolysis source power, and reaction temperature. Data for DCPA measurements, using Methylene Blue and Rose Bengal, are reported for the model substrates ascorbic acid, epinephrine, nicotine, and caffeine. Appropriate operating conditions yield low micromolar limits-of-detection and 1 YO precision.

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“…C.V. is known to specifically oxidize SH-groups in proteins to SO3-groups by photosensitization (1,9). Fig.…”

Section: Resultsmentioning

confidence: 99%

Functional Asymmetry in Excitable Surface Membrane of Protoplasmic Droplet Isolated from <I>Nitella</I> by Photosensitized Oxidation

Ueda

Muratsugu

Kobatake

1976

Cell Struct. Funct.

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ABSTRACT.Photooxidations of protoplasmic droplets of Nitella were performed by crystal violet (C.V.), rose bengal (R.B.) and methylene blue (M.B.) from the inside or outside of the membrane.Various physical properties of the droplet were examined. External treatment of the membrane by C.V. induced a temporary increase of resistance and a gradual depolarization of the membrane potential. Excitability disappeared after the depolarization, but the surface tension remained constant. Both membrane potential and resistance remained constant when the droplet was modified by C.V. from the inside, and the excitability was retained. Tension at the surface, however, decreased sharply by a factor of 100. Internal application of R.B. decreased resistance and depolarized the membrane potential by a maximum 20 mV. External treatment with R.B. caused a temporary decrease of resistance with depolarization by about 100 mV. Adsorption of M.B. on the surface membrane led to a decrease in resistance without changing the membrane potential under light illumination, and this was followed by abrupt depolarization. These results indicate that membrane potential and excitability of the protoplasmic droplet are governed largely by the structure at the outermost surface between the protoplasm and external solution and that the tension at the surface is maintained by the internal structure of the protoplasm. 155 Plasma membranes of cells are generally located in an extremely asymmetric environment, i.e., the concentration differences of ionic species on the two sides of the membrane vary by a factor of over 100, the electrical potential differs by 50 to 100 mV and the intracellular potential is negative with respect to the external solution. It is not unreasonable to assume that membranes may have a high anisotropic structure.The asymmetric organization of proteins in erythrocyte membrane was examined by Bender, Garan and Berg (2), Bretcher (3), Phyllips and Morison (12), Sergest et al. (13) and Zwaal, Roelofsen and Colley (20) by treating the membrane with non-penetrating reagents. Asymmetric distributions of phospholipids were reported by Bretcher (4), Stanley, Gordesky and Marinetti (14) and Zwaal, Roelofsen and Colley (20) who studied erythrocyte membranes by digesting phospholipids with specific enzymes. Among these findings, it is interesting to note that the molecular composition of both the proteins and phospholipids differs between the intact and ghost cell membranes (15).Functional asymmetry in the excitable membrane has been studied only in internally perfused squid giant axons. Tasaki (16) demonstrated that internal and external

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Influence of dye binding on the sensitized photooxidation of amino acids

Cited by 85 publications

References 23 publications

Investigations into the relationship between structure and function of diphtheria toxin.

Investigations into the relationship between structure and function of diphtheria toxin.

Dye-sensitized continuous photochemical analysis. Identification and relative importance of key experimental parameters

Functional Asymmetry in Excitable Surface Membrane of Protoplasmic Droplet Isolated from <I>Nitella</I> by Photosensitized Oxidation

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