Enzyme

In her room aboard the Doctor's TARDIS, Nyssa had got a microscope, used p.e. to study enzymes. (TV: Terminus)

The Seventh Doctor found the Kortani reeked of "bloodlust" in their enzymes. (PROSE: Peaceable Kingdom)

In 2017, Agrofuel Research Operations worked on Enzyme C36 and used enzyme EC 31 to genetically modify a sample of Raoultella planticola. (TV: The Pyramid at the End of the World)

In late 2018, Jade McIntyre at Sheffield Hallam University was working on an enzyme to increase the lifespan of spiders.

In the early 2020s, the Thirteenth Doctor observed birds natural enzymes fighting back Praxeus at Suki Cheng's laboratory. Suki Cheng proposed that if they isolated and boosted the enzymes, then splice them, they'd have one supercharged virus.