The luminescence properties of concanavalin A

Miller, James N.; Nwokedi, G.I.C.

doi:10.1016/0005-2795(75)90071-9

Cited by 7 publications

(3 citation statements)

References 25 publications

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“…Most of the binding experiments, however, involved quenching of MUM fluorescence. In agreement with Miller and Nwokedi (1975), no appreciable quenching of protein fluorescence was observed upon binding nonchromophoric mannose derivatives to con A saturated with Ni2+ and Ca2+. Any such apparent decrease of protein fluorescence upon addition of MUM was an artifact, caused by a filter effect of MUM and could not be restored upon addition of methyl a-D-mannopyranoside in large excess.…”

Section: Resultssupporting

confidence: 80%

Binding of 4-methylumbelliferyl α-D-mannopyranoside to tetrameric and unmodified or derivatized dimeric concanavalin A: equilibrium studies

Loontiens¹,

Clegg²,

Jovin³

1977

Biochemistry

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The binding of 4-methylumbelliferyl alpha-D-mannopyranoside (MUM) and concanavalin A, composed of intact polypeptide chains, was studied by equilibrium dialysis, difference spectroscopy, and fluorescence titration (Dean, B.R., and Homer, R.B. (1973), Biochim. Biophys. Acta. 322, 141-144), measured either at a fixed wavelength or above 350 nm. Dimeric and tetrameric concanavalin A samples were used under conditions of apparently full metal saturation. The results are consistent with a single carbohydrate-specific site per protomer, without interaction between sites; no indication for additional unspecific binding could be obtained. The values of the association constant are independent of the method or of the saturation range used and 4-methylumbelliferyl alpha-D-mannopyranoside, bound at a fractional saturation of 0.91 can be totally displaced by methyl alpha-D-mannopyranoside. The thermodynamic binding parameters for acetylated or succinylated concanavalin A, composed of intact polypeptide chains, were obtained by titration of total MUM fluorescence in the temperature range 9-39 degrees C. For unmodified dimeric concanavalin A at 25.0 degrees C, the values are K = (3.36 +/- 0.04) 10(4) M-1 with delta H degrees = -8.3 +/- 0.1 kcal mol-1 and delta S degrees = 7.2 +/- 0.3 eu; for tetrameric concanavalin A, the affinity is increased by 25% and within experimental error the values of delta H degrees and delta S degrees are identical to those for the dimeric protein. Derivatized concanavalin A shows binding characteristics that are entirely comparable to those of the native protein.

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Section: Resultssupporting

confidence: 80%

Binding of 4-methylumbelliferyl α-D-mannopyranoside to tetrameric and unmodified or derivatized dimeric concanavalin A: equilibrium studies

Loontiens¹,

Clegg²,

Jovin³

1977

Biochemistry

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“…Con-A has a lot of fascinating features. It agglutinates several cell kinds [28], demonstrates mitogenic activity in lymphocytes [29], and restrains the development of tumors [30]. Its responses to glycoproteins and soluble polysaccharides apparently look like antigenantibody interactions.…”

Section: Introductionmentioning

confidence: 99%

“…As soon as this position is engaged, a location that joins Ca 2+ is created; only totally metalized protein is competent to bind carbohydrates [33]. Within the acidic range of pH values (3.5-5.6), Con-A is a dimeric molecule (Mw 54 kDa), whereas at elevated pH values, Con-A tetramers and extra polymeric sorts are shaped [28,34]. Since Con-A is a metalloprotein, the existence of both Ca 2+ and Mn 2+ is necessary to preserve its coupling properties.…”

Section: Introductionmentioning

confidence: 99%

Laccase-Oriented Immobilization Using Concanavalin A as an Approach for Efficient Glycoproteins Immobilization and Its Application to the Removal of Aqueous Phenolics

2022

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An expanding number of human activities are contributing to the rising levels of aromatic compounds, which pose a major threat to the ecosystem. However, readily available microbial enzymes might be used to remediate contaminated wastewater in an economical and environmentally benign manner. In this study, an efficient method of laccase-oriented immobilization on modified Immobead 150P was proposed. The oriented immobilization technique using aminated laccase exceeds in both protein loading onto the carrier (4.26 mg/g) and immobilization yield (93.57%) due to the availability of more active sites. The oriented aminated laccase preserves 100% and 95% of its original activity after six and ten cycles of operation, respectively. The thermal stability performance of the oriented enzyme was the best among both free and random immobilized forms, since it was able to conserve 79% and 44% of its initial activity after 6 h at 50 °C and 60 °C, respectively. The ideal pH of oriented immobilized laccase was altered from 3.0 to 4.0, and it was more stable than both free and random immobilized laccases at pH 7.0. Finally, the integration of the adsorption capacity of Immobead 150P and the biodegradation ability of laccase promises the efficient removal of aqueous phenolics. Oriented immobilized laccase may provide a significant new approach for wastewater treatment, according to these findings.

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