Don't Show Unique Cutters in Bold
How do I turn off bold formatting for restriction enzymes that cut a sequence only once?

By default, SnapGene shows restriction enzymes that cut a sequence only once (unique cutters) in bold text.
Show Preferences

Click SnapGene → Preferences (macOS) or Edit → Preferences (Windows or Linux), and select "Enzymes" in the sidebar.
Uncheck the box to "Show unique cutters in bold".