Linamarase, or beta-D-glucosidase (EC 3.2.1.21), is an enzyme found in many plants including cassava and the butter bean.
When the plant is chewed or ground, it exposes the enzyme to compounds like linamarin and lotaustralin which release cyanide compounds that can be lethal to the eater.
This action of the enzyme is used by many cultures to process cassava into an edible substance.
The HCN then either dissolves readily in water or is released into the air.
Linamarase can be inhibited by low pH via a dilute acid.