Editing Serine (section)

== Biosynthesis ==
The biosynthesis of serine starts with the [[oxidation]] of [[3-phosphoglycerate]] (an intermediate from [[glycolysis]]) to [[3-phosphohydroxypyruvate]] and [[NADH]] by [[phosphoglycerate dehydrogenase]] ({{EC number|1.1.1.95}}). [[Reductive amination]] (transamination) of this ketone by [[phosphoserine transaminase]] ({{EC number|2.6.1.52}}) yields [[3-phosphoserine]] (''O''-phosphoserine) which is hydrolyzed to  serine by [[phosphoserine phosphatase]] ({{EC number|3.1.3.3}}).<ref name=Stryer1988>{{cite book | last1 = Stryer | first1 = Lubert | title = Biochemistry | date = 1988 | publisher = W.H. Freeman | location = New York | isbn = 978-0-7167-1843-7 | edition = 3rd | page = [https://archive.org/details/biochemistry3rdedi00stry/page/580 580] | url-access = registration | url = https://archive.org/details/biochemistry3rdedi00stry/page/580 }}</ref><ref>KEGG [http://www.genome.jp/dbget-bin/www_bget?ec:3.1.3.3 EC 3.1.3.3] etc.</ref>

In bacteria such as [[Escherichia coli|''E. coli'']] these enzymes are encoded by the genes serA (EC 1.1.1.95), serC (EC 2.6.1.52), and serB (EC 3.1.3.3).<ref>Uniprot: [https://www.uniprot.org/uniprot/P0AGB0 serB]</ref>
[[File:Serine biosynthesis.svg|class=skin-invert-image|left|thumb|400x400px|Serine biosynthesis]]

[[Serine hydroxymethyltransferase]] (SMHT) also catalyzes the biosynthesis of [[glycine]] (retro-aldol cleavage) from serine, transferring the resulting formalddehyde synthon to [[5,6,7,8-tetrahydrofolate]].  However, that reaction is reversible, and will convert excess glycine to serine.<ref>{{cite book | first1 = Albert L. | last1 = Lehninger | first2 = David L. | last2 = Nelson | first3 = Michael M. | last3 = Cox | title = Principles of Biochemistry | edition = 3rd | publisher = W.&nbsp;H. Freeman | location = New York | year = 2000 | isbn = 1-57259-153-6 | url-access = registration | url = https://archive.org/details/lehningerprincip01lehn }}</ref> SHMT is a [[pyridoxal phosphate]] (PLP) dependent enzyme.<ref name="Stryer1988"/>