Whats Serine?

Answer 1

A storage source of glucose by the liver and muscles; helps strengthen the immune system by providing antibodies; synthesizes fatty acid sheath around nerve fibers.
http://www.always-youthful.com/definitions/s.shtml

a sweetish crystalline amino acid involved in the synthesis by the body of cysteine
http://wordnet.princeton.edu/perl/webwn

Serine is one of the 20 most common natural amino acids on Earth.
http://en.wikipedia.org/wiki/Serine

Answer 2

Its one of the 20 amino acids found in the human body. These small molecules are joined together to form proteins. Proteins make up much of the body, such as muscle, hormones, enzymes and transporters (red blood cells are made of protein and transport oxygen) among other things.
Serine is a polar molecule. This means that it is soluble in water because it has a hydrogen and an oxygen on its side chain.
It can be made by the body from glycine, (another amino acid) so is termed "non-essential", that is we dont need to eat food that contains serine already preformed. The storage molecule in the liver and muscles is glycogen. This is an insoluble sugar derivative. To synthesise it or degrade it requires an enzyme called phosphorylase which phosphorylates serine. This then binds to glycogen and reconfigures it for release or storage.