Source: The Collaborative International Dictionary of English v.0.48
ligase \ligase\ n. (Biochem.)
An enzyme which catalyzes creation of a covalent bond between
two substrates, resulting in a larger product which is a
combination of the two starting materials; especially, DNAligase, an enzyme which creates a phosphate bond between 5'
and 3' ends of a DNA chain, resulting in a longer chain of
DNA. DNA ligase is important in normal biosynthesis of DNA in
the replication cycle of cells.
[PJC]