activator
n. countable C1 Advanced US //ˈæktəˌveɪtɝ// UK //ˈæktɪvˌeɪtɐ// ac·ti·va·tor
n. a substance that starts a chemical reaction or makes a process happen faster. In biology, it can also be a protein that turns on a gene.
n. a substance that initiates or accelerates a chemical reaction; in genetics, a protein that binds to DNA to increase the transcription of a specific gene.
In the mining industry, a chemical activator is often added to the water to help separate the valuable minerals from the waste rock.
The research team identified a specific transcriptional activator that binds to the promoter region, effectively switching on the gene responsible for the plant's drought resistance.
From activate + -or.