 The two enantiomers of each pair generally have vastly different biological properties.2-Ketohexoses are stable over a wide pH range, and with a primary p"K"a of 10.28, will only deprotonate at high pH, so are marginally less stable than aldohexoses in solution.The aldohexose that is most important in biochemistry is -glucose, which is the main "fuel" for metabolism in many living organisms.