Adjective modifier

• n-terminal: A conserved N-terminal threonine is involved in catalysis at each active site.

Modifies a noun

• residue: The kinase phosphorylates the CDKs on a threonine residue which lies within the activation segment, a modification essential for generating kinase activity.

• dehydratase: This enzyme is believed to be involved in the biosynthesis of isoleucine in methanogens and possibly other species lacking threonine dehydratase.

• kinase: CKI represents a unique group of serine / threonine protein kinases that is ubiquitously expressed in eukaryotic organisms.

• metabolism: In this particular exercise we want to find all genes involved in the widest sense in the threonine metabolism.

Preposition: in

• segment: Plks have a threonine in the activation segment whose phosphorylation is essential for activity.