diff --git a/R/deadEndMetabolite.R b/R/deadEndMetabolite.R
index f74c8c507040f35cb7833ef52aa8e2067fbbe604..b5fe7b14eed39c3a3306deffe7f5e031c5d11768 100644
--- a/R/deadEndMetabolite.R
+++ b/R/deadEndMetabolite.R
@@ -95,7 +95,7 @@
                     # dead end list: test all reactions k > j
                     k <- j+1
                     while (k <= length(nz)) {
-                        if ( (tmp_mat[i, nz[k]] != tmp_mat[i, nz[j]]) ||
+                        if ( ( sign(tmp_mat[i, nz[k]]) != sign(tmp_mat[i, nz[j]]) ) ||
                              (lb[nz[k]] < 0)        ||
                              (lb[nz[j]] < 0) ) {
                             #print(paste(i,":",k))
diff --git a/inst/NEWS.Rd b/inst/NEWS.Rd
index 414e4ca2e9331579f738b4fa20649d6723b40fea..0b5d4ac1358f939ad9c0edfa0989ad38f6d0782b 100644
--- a/inst/NEWS.Rd
+++ b/inst/NEWS.Rd
@@ -6,6 +6,12 @@
 
 \newcommand{\CRANpkg}{\href{http://CRAN.R-project.org/package=#1}{\pkg{#1}}}
 
+\section{Changes in version 1.3.1 2015-08-06}{
+  \itemize{
+    \item \code{deadEndMetabolite()} could miss deadEndMetabolites if reactions differ in stoichiometry e.g. 1 and 2.
+  }
+}
+
 \section{Changes in version 1.3.1 2015-08-06}{
   \itemize{
     \item \code{readTSVmod} had a mistake in the documentation about singletons.