The theme of this thesis was to quantify possible sources of adenosine triphosphate (ATP) hydrolysis in the human red blood cell (RBC). Understanding the consumption of ATP in RBCs provides insight into its energy demands, and those of other cell types and the body as a whole. The main sources of ATP hydrolysis investigated included: (i) the Na+,K+-ATPase (NKA); and (ii) cell membrane flickering (CMF) of RBCs.
In addition to these studies, we developed mathematical models of RBC systems and the experimental techniques used. Many of these models described spectral characteristics of NMR spectra, including: (i) chemical shift differences induced by shift reagents (SRs); (ii) dynamic nuclear polarisation (DNP) NMR; and (iii) z-spectra of quadrupolar nuclei contained in stretched hydrogels. In each of these cases, experimental data were acquired, and methods were then developed to estimate model parameter values.
This included (a) examined the NMR chemical shift differences induced on 23Na+ by the SR,TmDOTP, as functions of Na+ and other competing ions; (b) the mathematical description of the decay of magnetisation of hyperpolarised nuclei (achieved using DNP) as observed using 13C NMR spectroscopy; (c) the application of Bayesian analysis and Markov chain Monte Carlo (MCMC) methods to estimate the relaxation rate constants of the z-spectra of quadrupolar nuclei contained in stretched gels; (d) measurement of the stoichiometric relationship between the rate at which Na+ ions are transported across the RBC membrane by the NKA to its indirect consumption rate of glucose and (e) an exploration into the origin of CMF in human RBCs using both an experimental approach and mathematical modelling.
Overall, this work ruled out a number of potential sources of ATP hydrolysis in the RBC, and provided several model frameworks that describe metabolic systems in the human RBC, and various NMR spectral characteristics.