Notes: 4-Nitrophenyl α-L-rhamnopyranoside is a colorimetric substrate for naringinase.{52136} Upon hydrolysis by the α-rhamnosidase subunit of naringinase, 4-nitrophenol is released which can be quantified by colorimetric detection at 405 nm as a measure of naringinase α-rhamnosidase activity. 4-Nitrophenyl α-L-rhamnopyranoside has been used in the detection of naringinase α-rhamnosidase activity in various bacteria.