The kinetics of periodate oxidation of carbohydrates 2. Polymeric substrates.
A study of the kinetics of periodate oxidation on a series of dextran oligomers and polymers is carried out by isothermal microcalorimetry. In addition to these substrates, some dimeric carbohydrates and hyaluronan were studied. Rate constants were calculated from the calorimetric decay curves, which, properly corrected for calorimetric response, are proportional to the rate of periodate conversion. The dependence of the kinetic rates on the molecular weight of dextran samples and on the substrate concentration, is described in terms of the much higher rates of terminal reducing units. The presence of two sites with comparable reaction rates makes the analysis of the calorimetric curves difficult, even in the simple overall pseudo-first-order condition. The suitability of a phenomenological treatment of kinetic data is explored.
Tiziani
Stefano
S
Department of Biochemistry, Biophysics and Macromolecular Chemistry, Laboratory of Physical and Macromolecular Chemistry and INSTM, UdR Trieste, University of Trieste, Via Giorgeri 1, Italy.
Sussich
Fabiana
F
Cesàro
Attilio
A
D002151:Calorimetry / Q000379:methods; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry; D003911:Dextrans / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008970:Molecular Weight; D010084:Oxidation-Reduction; D010504:Periodic Acid / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D013816:Thermodynamics; D013997:Time Factors
D002241:Carbohydrates; D003911:Dextrans; D011108:Polymers; D010504:Periodic Acid