Added pKon and pKoff; restructured enum, and added more descriptions

biolink-model.yaml

@@ -13569,18 +13569,37 @@ enums:
 
   AffinityParameterEnum:
     description: >-
-      The types of parameters that can be used to describe the affinity between two entities, characteristically chemicals and proteins.
+      The types of parameters that can be used to describe the affinity between two entities,
+      characteristically chemicals and proteins. The values are generally 
+      stated as the negative base 10 logarithm of the raw measurements.
     permissible_values:
       "pIC50":
         description: >-
-          Negative logarithm of the molar concentration of a chemical that produces a 50% inhibition of a function
+          Negative base 10 logarithm of the the inhibitory concentration 50% (IC50)
+          measures the concentration needed to block or inhibit a biological response.
       "pEC50":
         description: >-
-          Negative logarithm of the molar concentration of a chemical that produces a 50% excitation of a function
+          Negative base 10 logarithm of the molar concentration of
+          a chemical that produces a 50% excitation of a function
       "pAC50":
       "pXC50":
       "pKi":
+        description: >-
+          Negative base 10 logarithm of the equilibrium binding affinity for a ligand that reduces
+          the activity of its binding partner. Ki represents the concentration at which the
+          inhibitor ligand occupies 50% of the receptor sites when no competing ligand is present
+      "pKon":
+        description: >-
+          Negative base 10 logarithm of the association rate constant (Kon) describes
+          the rate at which molecules bind to each other.
+      "pKoff":
+        description: >-
+          Negative base 10 logarithm of the dissociation rate constant (koff) describes
+          the rate at which they dissociate.
       "pKd":
+        description: >-
+          Negative base 10 logarithm of the equilibrium dissociation constant (KD) which
+          is a measure of the binding affinity and is defined as the ratio of koff to kon.
 
   FDAIDAAdverseEventEnum:
     description: >-