RESUMEN
A study was made of the influence of a number of biochemical parameters of blood serum on a value of the time of spin-grid relaxation of serum water protons (T1). An increase in protein concentration as well as a decrease in the fraction of serum globulins resulted in a decrease in a T1 value, which can be accounted for within the framework of a model of rapid exchange in the "free"-"bound" water system as a result of change in the total value of a water absorbing surface. The influence of dissolved oxygen of a paramagnetic element on the relaxation of serum water protons is under discussion.
Asunto(s)
Fenómenos Fisiológicos Sanguíneos , Espectroscopía de Resonancia Magnética/métodos , Fenómenos Biofísicos , Biofisica , Agua Corporal/química , Humanos , Espectroscopía de Resonancia Magnética/instrumentación , Oxígeno/sangre , Presión Parcial , Protones , Albúmina Sérica/análisis , Seroglobulinas/análisis , Factores de TiempoRESUMEN
Interaction of low-molecular ligands (LML) isolated from blood serum albumin (SA) and serum proteins leads to higher T1 values for water protons compared with those observed in LML-free solutions, although the total amount of bound water increases. The latter was revealed by low-temperature NMR spectroscopy, as well as by the amount of water sorbed on SA + LML at a relative humidity P/Ps greater than 0.7. In the region 0.2 less than P/Ps less than 0.6 the amount of SA + LML-sorbed water decreased, as compared with that in SA indicating that the oppositely charged groups of LML screen some charged groups of the protein. A decrease of charge-to-charge interactions in solution, or with a high water content, leads to the hydration of those groups. The increase of the T1 value for water protons in solution is, probably, due to a hindered exchange between the sorbed water and bulk water. It is outlined that charge interactions between macromolecules may significantly affect water sorption by proteins.