According to his first book, how was john smith set free?
&
according to his second book, how was john smith set free?

G protein-coupled receptors (GPCRs), or seven transmembrane receptors (7TMs), are the largest family of cell-surface molecules involved in signal transmission (Rebert 2007). GPCRs have drawn much attention for treating hypertension, neurological, pain and other disorders, as more than 40% of the clinically marketed drugs are targeting GPCRs.

https://www.creative-biogene.com/Services/Drug-Discovery-Services/GPCR-Screening-Assays.html

Explanation:

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products