Impact of supramolecular interactions of dextran-β-cyclodextrin polymers on invertase activity in freeze-dried systems

β-cyclodextrin-grafted dextrans with spacer arms of different length were employed to evaluate the impact of supramolecular interactions on invertase activity. The modified dextrans were used as single additives or combined with trehalose in freeze-dried formulations containing invertase. Enzyme activity conservation was analyzed after freeze-drying and thermal treatment. The change of glass transition temperatures (Tg) was also evaluated and related to effective interactions. Outstanding differences on enzyme stability were mainly related to the effect of the spacer arm length on polymer-enzyme interactions, since both the degree of substitution and the molecular weight were similar for the two polymers. This change of effective interactions was also manifested in the pronounced reduction of Tg values, and were related to the chemical modification of the backbone during oxidation, and to the attachment of the β-cyclodextrin units with spacer arms of different length on dextran.Fil: Santagapita, Patricio Roman. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mazzobre, Maria Florencia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Buera, Maria del Pilar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ramírez, Héctor L.. Universidad de Matanzas Camilo Cienfuegos.; CubaFil: Gómez Brizuela, Leissy. Universidad de Matanzas Camilo Cienfuegos.; CubaFil: Corti, Horacio Roberto. Comisión Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones No Nucleares. Gerencia Física (CAC). Departamento de Física de la Materia Condensada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Villalonga Santana, Reynaldo. Universidad Complutense de Madrid; Españ

The crystal structure of 6I-(6-aminohexyl)amino-6I-deoxycyclomaltoheptaose.

International audienceThe monosubstituted cyclomaltoheptaose derivative, 6I-(6-aminohexyl)amino-6I-deoxycyclomaltoheptaose, crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a = 32.513(2), b = 15.3871(9), c = 15.2645(9) A, V = 7636.6(8) A3 and Z = 4. The macrocycles are spirally aligned along the twofold screw axis parallel to the c crystal axis forming polymeric-like columns. The 6-aminohexyl chain enters the cavity of an adjacent cyclomaltoheptaose moiety in the column from the secondary side and its extremity protrudes from the primary side of the latter. All the atoms of the chain exhibit high thermal motion.The monosubstituted cyclomaltoheptaose derivative, 6I-(6-aminohexyl)amino-6I-deoxycyclomaltoheptaose, crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a = 32.513(2), b = 15.3871(9), c = 15.2645(9) A, V = 7636.6(8) A3 and Z = 4. The macrocycles are spirally aligned along the twofold screw axis parallel to the c crystal axis forming polymeric-like columns. The 6-aminohexyl chain enters the cavity of an adjacent cyclomaltoheptaose moiety in the column from the secondary side and its extremity protrudes from the primary side of the latter. All the atoms of the chain exhibit high thermal motion

Controlling Cu•••Cu distances using halides: (8-phenylthionaphth-1-yl)diphenylphosphine copper halide dimers

In the isomorphous binuclear Cu2X2L2 systems (L = (8-phenylthionaphth-1-yl)diphenylphosphine the Cu center dot center dot center dot Cu separation is reduced as the halide size increases.PostprintPeer reviewe