Dr. Lanyi studies the physiology, biochemistry, and the molecular mechanisms of ion translocation across biological membranes. His work focuses on the light driven electrogenic ion pump in the cytoplasmic membrane of Halobacterium halobium, bacteriorhodopsin, an outward directed proton pump). This purple pigment is a small protein in which retinal isomerization after photon absorption initiates molecular rearrangements and results in ion uptake on one side of the membrane, translocation, then release on the other side. Individual steps of the photocycles are followed by flash-spectroscopy with a gated optical multichannel analyser, which reveals the rise and decay of several intermediate species with red- and blue-shifted absorption spectra. The measured difference spectra are deconvoluted, using computer intensive grid-search, into component spectra. The relative weights of these spectra are the time-dependent concentrations of the intermediates, from which the kinetics are reconstructed. The kinetic models reveal the steps for internal transfers of proton and chloride, and their release and uptake at the membrane surfaces during transport.