Most people who use a DNA extraction kit do not need to know the biochemistry of the proteinase that lyses the cells. The kit should just work. But for researchers designing new applications, troubleshooting unusual sample types, or evaluating a chemistry for validation purposes, the underlying enzyme science matters and until now, it has existed primarily in patent literature and internal documentation.

A 2025 paper in FEBS Letters (Broomfield, Wilbanks, and Saul) characterises the neutral metalloprotease from Geobacillus sp. EA1, the thermophilic proteinase at the core of Exymes extraction kits, using mass spectrometry to map its substrate cleavage preference.

The key findings: the enzyme is a zinc-dependent neutral metalloprotease with structural similarity to thermolysin, the well-characterised Bacillus thermoproteolyticus protease. However, unlike thermolysin, the EA1 enzyme does not display a strong preference for leucine at the P1-prime position. Its cleavage preference is distinct, and this difference has practical consequences for the substrates it degrades efficiently in the context of a cell lysis reaction.

The temperature-activity profile which is inactive at ambient temperature, highly active at 75°C, completely inactivated at 95°C, is precisely what enables the sequential enzyme protocol at the heart of the extraction chemistry. That behaviour is now characterised in the peer-reviewed literature for the first time.

For laboratories considering Exymes chemistry for a new or unusual sample type, or seeking to understand inhibition profiles and protocol boundaries, this paper provides the biochemical foundation that has previously been unavailable in published form.