Natural Science Forum / Chemistry / Organic Synthesis / July 2006

Hi,

Please help me to understand this.

Example. You wish to prepare a 2mM solution of NADP, and find that
anhydrous weight of NADP is 743. But you have purchased monosodium salt
containing four molecules of water, and the label states that the
preparation is 94% pure. The mol weight of monosodium NADP with four
molecules of water is then 743+23-1+(4x18) = 837.

Questions;
1) why do we add molecular weight of Sodium to 743?
 2) Why substract 1 (hydrogen?) ?

Thank you