diff --git a/prody/proteins/ciffile.py b/prody/proteins/ciffile.py
index 5000e30bc..7a8f82bcb 100644
--- a/prody/proteins/ciffile.py
+++ b/prody/proteins/ciffile.py
@@ -46,7 +46,7 @@ class MMCIFParseError(Exception):
 
     :arg altloc: if a location indicator is passed, such as ``'A'`` or ``'B'``,
          only indicated alternate locations will be parsed as the single
-         coordinate set of the AtomGroup, if *altloc* is set **True** all
+         coordinate set of the AtomGroup, if *altloc* is set ``'all'`` then all
          alternate locations will be parsed and each will be appended as a
          distinct coordinate set, default is ``"A"``
     :type altloc: str
diff --git a/prody/proteins/pdbfile.py b/prody/proteins/pdbfile.py
index f76ae619a..3d0366479 100644
--- a/prody/proteins/pdbfile.py
+++ b/prody/proteins/pdbfile.py
@@ -64,7 +64,7 @@ class PDBParseError(Exception):
 
     :arg altloc: if a location indicator is passed, such as ``'A'`` or ``'B'``,
          only indicated alternate locations will be parsed as the single
-         coordinate set of the AtomGroup,  if *altloc* is set **True** all
+         coordinate set of the AtomGroup,  if *altloc* is set ``'all'`` then all
          alternate locations will be parsed and each will be appended as a
          distinct coordinate set, default is ``"A"``
     :type altloc: str