DNA fragmentation

Its main units of measurement is the DNA Fragmentation Index (DFI).

CAD is normally inhibited by another protein, the Inhibitor of Caspase Activated DNase (ICAD).

[9] CAD cleaves the DNA at the internucleosomal linker sites between the nucleosomes, protein-containing structures that occur in chromatin at ~180-bp intervals.

The linker sites are the only parts of the DNA strand that are exposed and thus accessible to CAD.

[12][13] Using bright-field microscopy, the SCD test appears to be more sensitive than the TUNEL assay.

A DNA double strand wrapped around a core of histone proteins
A nucleosome , consisting of DNA (grey) wrapped around a histone tetramer (coloured). In apoptotic DNA fragmentation, the DNA is cleaved in the internucleosomal linker region, which is the part of the DNA not wrapped around the histones.