DNA toposisomerase I is a key nuclear enzyme that interconverts supercoiled DNA to the required topological conformations for normal DNA replication and transcription. This enzyme is the target antigen for the so-called Scl-70 autoantibodies. Scl-70 antibodies are a specific marker in scleroderma patients (specificity 98-100%) and are associated with the presence of diffuse skin involvement and pulmonary fibrosis.
In human tissues the DNA topoisomerase I is initially synthesized as a protein with a molecular weight of 100 kDa. Most of this precursor is then proteolytically processed to a 70-kDa size, from which the Scl-70 antigen has derived its name.
To allow optimal assay development DIARECT offers three distinct DNA topoisomerase I antigens:
the non recombinant, bovine DNA Topoisomerase I antigen,
a recombinant, full-length 100-kDa enzyme precursor and
a recombinant, truncated form resembling the processed 70-kDa form of the antigen.
DNA Topoisomerase I (non recombinant; bovine) from DIARECT is purified from bovine tissue.
Availability on request. Please inquire.