The phrase "active only when" is correct and usable in written English.
It can be used to describe a condition or state that occurs exclusively under certain circumstances.
Example: "The alarm system is active only when the building is unoccupied."
Alternatives: "operational solely when" or "functioning exclusively when".
ErbB-3 and -4 can form homodimers, but whereas ErbB-4 homodimers are active, ErbB-3 has impaired kinase activity and is active only when dimerized with another family member [ 7].
In support of this model, the phosphatase Slingshot-1L, which dephosphorylates and activates cofilin, is active only when bound to actin filaments (Nagata-Ohashi et al., 2004; Soosairajah et al., 2005) and would thus be predicted to be less active in juxtamembrane regions.
The "Black Widow" model for transcription activation suggests that certain transcription factors are active only when unstable and their ubiquitylation status positively correlates with their activity.
For example, fractional activation for a substrate that is active only when phosphorylated is equivalent to the ratio of phosphorylated to total protein.
An HNC can be thought of as a highly specialized functional unit that 'responds' by becoming fully active only when a specific brain activation pattern − brought about by the sensory (or internal) stimulation − conveys at least a critical amount of activation in its neuronal circuits.
Therefore, theoretically the reporter would be active only when all the components required for activation were present, including ligand, co-receptors, and a complete co-activation complex.
Some became politically active only last summer, when 500,000 people marched in a successful effort to force the government to withdraw plans for a stringent internal-security law.
"I will resume active campaigning only when I am certain that my daughter is O.K. and getting the help she needs," Ms. McFarland said in a statement yesterday.
He returned to active leadership only when a politburo delegation visited him and told him that steps needed to be taken immediately so as to improve the situation at the front.
KBOs become active comets only when they swoop near the sun, but CW Leonis, running low on nuclear fuel, has ballooned out to the distance of Jupiter from our sun and blazed to 5000 times its normal luminosity.
Xylanase fused to Zera was biologically active not only when solubilized from PBs but also in its insoluble form.
