RAT LYSYL HYDROXYLASE - MOLECULAR-CLONING, MESSENGER-RNA DISTRIBUTIONAND EXPRESSION IN A BACULOVIRUS SYSTEM

A cDNA library from rat lung was screened with a chicken lysyl hydroxy lase cDNA, and several overlapping rat lysyl hydroxylase cDNAs were is olated. The complete cDNA was 91 and 77% identical, respectively, to t he human and chicken lysyl hydroxylase cDNAs at the protein level. By Northern blot, the rat lysyl hydroxylase cDNA recognized a single 3.2 kb mRNA that was present in a wide variety of rat tissues. In order to further confirm the identity of this cDNA, the cDNA was expressed in insect cells via a baculovirus vector. These cells produced an 85 kDa protein with lysyl hydroxylase activity. The recombinant lysyl hydroxy lase had a specific activity and K-m values for its substrates that we re similar to those of the enzyme isolated from chick embryos. The fac t that this single lysyl hydroxylase cDNA encodes a protein sufficient for lysyl hydroxylase activity is consistent with previous biochemica l findings that lysyl hydroxylase only requires a single type of subun it for its activity.