In their landmark 1987 paper, Hon Cheung Lee and colleagues discovered not one but two Ca2+-mobilizing second messengers, cADPR and NAADP from the effects of nucleotides on Ca2+ release in sea urchin egg homogenates. It turns out that NAADP was a contaminant in commercial sources of NADP, but it was not until 1995 that its structure was solved.
In their significant 1987 paper, Hon Cheung Lee and colleagues identified not one but two Ca2+-mobilizing second messengers, cADPR and NAADP from nucleotide-induced Ca2+ release in sea urchin egg homogenates. It was later discovered that NAADP was a contaminant in commercial NADP sources, though its structure was elucidated only in 1995.