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Applications:
GPC
- CELLULOSE IN BEAD FORM: PROPERTIES RELATED TO CHROMATOGRAPHIC USES
- Peska J., Stamberg J., Hradil J., Ilavsky M.: J.
Chromatogr., 125 (1976) 455-469
Cellulose in the form of regular beads was characterized by its swelling, porosity,
deformability of the individual particles expressed as the penetration modulus, and the
permeability of layers in chromatographic columns. The bead cellulose possesses sufficient
mechanical strenght while having a considerable porosity; the flow resistance is in good
accord which the spherical shape of the particles, and the allowed flow stress lies within
technically useful limits. Bead cellulose has been tested as a packing in gel
chromatography, and it is expected that it can be used advantageously in other
chromatographic methods also, not only in its basic unsubstituted state, but also in the
form of derivatives.
- REGENERATED CELLULOSE IN THE BEAD FORM: AFTERTREATMENTS AND THEIR
EFFECTS ON THE POROUS STRUCTURE OF CELLULOSE
- Peska J., Stamberg J., Pelzbauer Z.: Cell. Chem.
Technol., 21 (1978) 419-428
High porous regenerated cellulose was prepared in the form of spherical regular
particles with dimensions ranging from tens to hundreds of um. The pore volume fraction
filled with water reached 90 %. SEM of samples dried by the critical point method showed a
very divided surface pores up to as much as 1 um. Direct drying from water yielded
glass-transparent nonporous spheres with a distined microstructure on the surface, which
after swelling in water exhibited a pore volume fraction of ca. 55 %. Water in the
original spherical product was replaced by organic solvents while preserving the porous
structure. By introducing a monomer and its radical polymerization, the porous structures
of the spheres were fixed to permit investigation by transmission EM. It was found that
the elementary morphological unit consists of globules, 30 - 40 nm in size, forming
agglomerations with dimensions larger by an order of magnitude.
Drying from organic solvents yielded products which were porous in the dry state and the
pore volume fraction of which depended on the nature of the solvent. SEM of samples dried
from benzene or diethyl ether showed structure similar to those obtained after treatment
by the critical point method.
- PERLOZA - PRODUCTS MADE OF REGENERATED BEADED CELLULOSE
- Krepelka I.: Cellucon ´92, Selective
Purification and Separation Processes: The Role of Cellulosic Materials,
p. 41, July 27-30, 1992, The North East Wales Institute, Cartrefle College,
Wrexham, Clwyd, UK
Perloza MT are gel filtration media suitable for a number of
chromatographic separations. Gels are available in four types with different particle size
grades.
Perloza ST is dry regenerated cellulosecomposed of spherical particles.
It is used as initial material for the preparation of all basic types of ion exchange and
for a number of further modified derivatives of spherical cellulose. Perloza ST is
available in different particle size grades from 30 µm to 400 µm.
Perloza SF is pure dry beaded cellulose. It is sterilised by radiation.
Perloza SF is suitable for pharmaceutical applications as powdered cellulose.
Gels are hydrophilic, high stable characterized by:
- outstanding mechanical stability allows high throughput up to several bar without
damaging of matrices
- high chemical stability allows the use of a wide range of pH and salt solution, gels
may be cleaned with 0.2 M NaOH and may be autoclaved
- negligible change in swelling volume with change of eluent
- small particle size and narrow particle size distributionbr
- free hydroxyl groups on the matrix allow preparation of derivatives especially ideal
for preparation of affinity gels for bioaffinity chromatography
- broad fractionation range allows fractionating especially large molecules
- low non-specific adsorption
- SIZE-EXCLUSION EFFECT OF A SUBSTRATE UPON KINETICS OF TRYPSIN IMMOBILIZED ON
POROUS BEAD CELLULOSE. 1. INFLUENCE OF DISTRIBUTION COEFFICIENT OF A SUBSTRATE
- Gemeiner P., Polak C., Breier A., Petrus L., Benes
M.J.: Enzyme Microb. Technol., 8
(1986) 109-114
A model of heterogeneous biocatalysis, in which kinetics and partition effects are
connected via the size-exclusion principle, was worked up experimentally and
theoretically. The present paper shows that the maximum relative activity of trypsin (EC
3.4.21.4) immobilized on porous bead (spherical) cellulose is directly proportional to the
available distribution coefficient of the substrate. Providing that the excess of
substrate is not sufficient (e.g. S/Km ~ 1) to safeguard saturated enzyme kinetics, the
originally linear relationship of Ra versus Kav turns to an exponential one,
without any dependence upon the manner of enzyme immobilization. It is suggested that the
above may be a result of partition resistance and that the main fractrs determining the
shape of the Ra versus Kav, relation in conditions of substrate shortage are
the size and geometry of the matrix. The physical characteristics of the porous carrier as
well as the manner of covalent immobilization of the enzyme are all reflected in the
constants applied in the derived equations.
- SIZE-EXCLUSION EFFECT OF A SUBSTRATE UPON KINETICS OF TRYPSIN IMMOBILIZED ON
POROUS BEAD CELLULOSE. 2. INFLUENCE OF HYDRODYNAMIC DIAMETER OF A SUBSTRATE
- Gemeiner P., Barteltova L., Soltes L., Breier A.:
Enzyme Microb. Technol., 9 (1987)
44-46
The present paper deals with the dependence of the relative activity ( Ra )of
the immobilized enzyme on the hydrodynamic diameter h of the substrate un
reaction-controlled conditions. The partition effect follows the size-exclusion principle.
This could be confirmed by the fact that the immobilized enzyme failed to become saturated
(e.g. S/Km ~ 1). The exponential form of the relation Ra versus h is
determined by the beometry of the matrix and/or posre and may be expressed by the model
describing an isotropic network of random planes in which all plane orientations are
equally represented. The constants of the exponential equation depend on the physical
properties of the matrix as well as on the mode of covalent immobilization, i.e. chemical
modification of the enzyme.
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