The double (N3P/I5P), triple (N3P/I5P/N238P and N3P/I5P/T 265P), and quadruple variants (N3P/I5P/N238P/T 265P) were all more stable than if the stability effects of the individual proline substitutions were added together.
Tvöföldu (N3P/I5P), þreföldu (N3P/I5P/N238P og N3P/I5P/T 265P) og fjórföldu (N3P/I5P/N238P/T 265P) prólínafbrigðin juku öll stöðugleika meira í samsettu prólínafbrigðunum en sem svaraði til stöðgunar vegna hverrar stakar prólín breytingar í einföldu stökkbrigðunum.