diff --git a/docs/enzymes.rst b/docs/enzymes.rst
index 7bd895241fc52fa3fddd0e51a5746f0804689547..aadbe33bdda5ebed79e2e996312420de86f9f2c7 100644
--- a/docs/enzymes.rst
+++ b/docs/enzymes.rst
@@ -1,3 +1,5 @@
+.. _enzymes:
+
 ===================
 Enzymes definitions
 ===================