2',3'-cyclic nucleotide phosphohydrolase activity determined using an image analyzer detection system. 
The activity of 2',3'-cyclic nucleotide phosphohydrolase (CNPase) was assayed using high-performance thin-layer chromatography (HPTLC) and an image analyzer detection system.  The assay system was used to study a possible inhibitory effect by aminoguanidine on CNPase specific activity.  One advantage of using a fixed-time HPTLC system over a real-time spectrophotometric system for an enzyme activity study was that apparent inhibition of the enzyme due to interference of the assay system (chromophore inhibition, etc.)  was avoided.  In addition, due to the increased accuracy of the image analyzer over conventional methods of TLC plate analysis, a rapid and more accurate measurement of HPTLC plates was possible which required only nanomole amounts of substrate.  Also, a digital image of each plate analyzed was stored indefinitely in the computer's memory for future reference.  The measurements of CNPase specific activity made using this system compared favorably to those found in recent literature.