Cleavage of N-Carbobenzoxy Groups by dry Hydrogen Bromide and Hydrogen Chloride

Ben‐Ishai, D.; Berger, Arieh

doi:10.1021/jo50012a002

Cited by 400 publications

(105 citation statements)

References 5 publications

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“…Cells (3-5 mg of cell protein/ml or approximately 5%o v/v) were incubated in Krebs-Ringer phosphate medium, pH 7.4, total volume 4 ml, for 10 min in siliconized 25 (8). Polylysyl-gelatin was prepared with N, N'-di-carbo-benzoxy-L-lysine anhydride (9,10 Rabbit antiserum to bovine albumin was purchased from Difco Laboratories, Detroit, Mich. Guinea pig blood was obtained by cardiac puncture and allowed to clot in glass containers.…”

Section: Methodsmentioning

confidence: 99%

Quantitative Studies of Phagocytosis by Polymorphonuclear Leukocytes: Use of Emulsions to Measure the Initial Rate of Phagocytosis

Stossel¹,

Mason²,

Hartwig³

et al. 1972

J. Clin. Invest.

218

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A B S T R A C T Polymorphonuclear leukocytes suspended in Krebs-Ringer phosphate medium ingest paraffin oil containing Oil Red 0 emulsified with a variety of substances. Spectrophotometric determination of Oil Red O in the cells after uningested particles have been removed by differential centrifugation provides a quantitative measure of phagocytosis. This system has been used to investigate the effects of several drugs and hormones on the initial rate of phagocytosis and to approach the question of how the surface of a particle influences its acceptability as a substrate for phagocytosis. The rate of uptake of paraffin oil emulsified with bovine albumin was constant for 6 min and was proportional to cell concentration when saturating concentrations of paraffin oil emulsion were used. At lower concentrations of substrate, the initial rate of phagocytosis was directly proportional to paraffin oil concentration. The increment in glucose oxidation associated with phagocytosis varied directly with the initial rate of particle uptake. The rate of ingestion of the albumin emulsion was not altered by serum (2-20%, v/v), glucose (5-20 mM), or omission of potassium from the medium. The rate of phagocytosis was decreased 65% if magnesium was omitted, and was essentially zero in the absence of divalent cations. The initial rate of uptake was inhibited by inhibitors of glycolysis, by Nethylmaleimide (0.05-1 mM), colchicine (0.001-0.1 mM), theophylline (1 and 2 mM), dibutyryl cyclic AMP (1 mM), hydrocortisone (2.1 mM), and ethanol (85 mM). Inhibitors of oxidative phosphorylation and dexamethasone (0.01 mM) were without effect, while insulin (2 mU/ml) slightly stimulated the phagocytic rate. Paraffin oil emulsified with different agents was used to approach the question of how the surface of a particle influences its acceptability as a substrate for phagocytosis. Emulsions prepared with nonionic detergents, methylated proteins, and proteins with a weak net charge at pH 7.4 were poorly ingested. On the other hand emulsions prepared with agents of strong net positive or negative charge were rapidly taken up. The effect of divalent cations on the rate of phagocytosis varied with the nature of the emulsifier, but was not related in any simple, direct fashion to the net surface charge of the particles. However, it has not been conclusively established that charge was the only variable of the emulsion particles employed. INTRODUCTIONPhagocytosis is an integrated series of complex events.Certain as yet unidentified characteristics of the surface of a particle cause it to be bound to the plasma membrane of a polymorphonuclear leukocyte which then internalizes it. As the phagocytic vesicle is formed and moves centripetally, lysosomal granules discharge their contents into it and disappear from the cytoplasm, a process termed degranulation. These processes are accompanied by several alterations in the metabolism of the phagocytic cell which have been termed metabolic concomitants of phagocytosis. One of these is an increase in oxidatio...

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Section: Methodsmentioning

confidence: 99%

Quantitative Studies of Phagocytosis by Polymorphonuclear Leukocytes: Use of Emulsions to Measure the Initial Rate of Phagocytosis

Stossel¹,

Mason²,

Hartwig³

et al. 1972

J. Clin. Invest.

218

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“…[27][28][29][30] Equilibrium studies. Protonation constants for L L and L L/C for formation of their acid salts and their complex stability constants were calculated by computer fitting of potentiometric data.…”

Section: Chartmentioning

confidence: 99%

Managing Tight Binding Receptors for New Spearations Technologies

GIVENS¹

2004

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“…Abz-Gly-Plze(NO2)-Pro. This compound was prepared by removal of the benzyloxycarbonyl group from the peptide Cbz-Abz-Gly-Phe(NO&Pro with HBr [21]. Peptide concentration was 0.1 g/ml and the 30% HBr in acetic acid reagent contained anisol (10%).…”

Section: Synthesis Of Peptidesmentioning

confidence: 99%

An Intramolecularly Quenched Fluorescent Tripeptide as a Fluorogenic Substrate of Angiotensin‐I‐Converting Enzyme and of Bacterial Dipeptidyl Carboxypeptidase

Carmel

Yaron

1978

European Journal of Biochemistry

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The N-acyltripeptide 2-aminobenzoylglycyl-p-nitrophenylalanylproline was synthesized and applied as a substrate in the assay of angiotensin-I-converting enzyme from calf lung and human serum, and of the bacterial dipeptidyl carboxypeptidase from Escherichia coli. This compound belongs to a new class of substrates for proteolytic enzymes, having the general structure F -X -Q in which fluorescence of group F is quenched by intramolecular interaction with the group Q. Enzymatic cleavage of the peptide chain (X stands for one or more amino acid residues) generates the unquenched F-containing derivative and the resulting fluorescence is used for quantitative measurement of the hydrolysis rate. Cleavage of the Gly-Phe(N02) peptide bond in the weakly fluorescent 2-aminobenzoylglycyl-p-nitrophenylalanylproline molecule results in appearance of the 71 times higher fluorescence (La, = 41 5 nm) of 2-aminobenzoylglycine. Continuous recording of the rising fluorescence allows convenient, sensitive and specific determination of the enzymatic activity, applicable to crude enzyme preparations and human serum. The activity of the mammalian enzyme, measured by this method, is enhanced by Cl-ions and inhibited by low concentrations of EDTA and [Asn', Val']angiotensin 11. Kinetic measurements showed Michaelis-Menten behavior, K, = 0.21 f 0

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Cleavage of N-Carbobenzoxy Groups by dry Hydrogen Bromide and Hydrogen Chloride

Cited by 400 publications

References 5 publications

Quantitative Studies of Phagocytosis by Polymorphonuclear Leukocytes: Use of Emulsions to Measure the Initial Rate of Phagocytosis

Quantitative Studies of Phagocytosis by Polymorphonuclear Leukocytes: Use of Emulsions to Measure the Initial Rate of Phagocytosis

Managing Tight Binding Receptors for New Spearations Technologies

An Intramolecularly Quenched Fluorescent Tripeptide as a Fluorogenic Substrate of Angiotensin‐I‐Converting Enzyme and of Bacterial Dipeptidyl Carboxypeptidase

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