BISC110: Series 3 Experiment 9 Hill Reaction: Difference between revisions

In 1937 Robert Hill showed that this partial reaction of the electron transport chain using DCPIP could be used to investigate the rate of oxygen evolution (from the splitting of water molecules in PSII) and thus the rate of photosynthesis in thylakoids of isolated chloroplasts.  The reaction is now known as the Hill reaction and is still used today to determine photosynthetic rates in chloroplast preparations.  

<br><br>

For the isolation of chloroplasts from spinach, a buffer is used since the leaves, when homogenized, can yield a low pH suspension.  In the initial isolation step, the sorbitol serves to maintain an osmotic potential similar to that of an intact leaf.  The divalent cation Mg2+, known to be important to membrane structure and function, is also included in the medium.  All isolation and fractionation steps are performed at 4 C to minimize proteolytic degradation of proteins.