In the dataframe described below, I can filter (by name) for "Signal transduction mechanisms" but I cannot filter for "ABC transporters [PATH:ko02010]" (I get a dataframe with empty rows).
test_2 <- filter(DF, grepl("ABC transporters [PATH:ko02010]", DF$C))
test_1 <- filter(DF, grepl("Signal transduction mechanisms", DF$C))
DF
B C
# 1 1 ABC transporters [PATH:ko02010]
# 2 2 ABC transporters [PATH:ko02010]
# 3 2 Signal transduction mechanisms
# 4 5 Signal transduction mechanisms