Enzymes catalyse reactions in biological processes and their presence in biological samples is of interest to a variety of Clinical, Industrial and Educational analysts. 

Several manufacturers offer test kits to enable determination of enzyme activity by Colorimetry.  The kits are designed so speed of reaction is dependent on enzyme concentration at a controlled temperature.  Whilst there are a wide variety of different enzymes, many kits use NADH, a co-enzyme which converts to NAD when reacted, to help determine the enzyme of interest; NADH adsorbs at 340nm and NAD does not.  During the reaction time interval, the rate at which NADH is converted to NAD is proportional to the concentration of the enzyme of interest and the measured decrease in absorption at 340nm is multiplied by a factor (supplied by the kit manufacturer) to determine enzyme concentration.

Sherwood Scientific’s M260UV CHROMA Colorimeter, is supplied with a 340nm interference filter and heated cuvette holder, and thanks to its “open programmability”, can be used with most commercially available test kits to determine enzymes concentration as described above.

The Model 260UV CHROMA Colorimeter is ideally suited to the task with:

• Rugged performance of a proven optical bench design
• 340nm functionality
• Heated cuvette holder (thermostated to 37°C)
• Programmability to accommodate kit manufacturer’s methodologies
• Facilities to record and time the reaction
• Calculation of the enzyme activity based on the change in absorbance

With addition of a printer the method details along with sample identifiers and results can be printed for a permanent record.

The Model 260UV colorimeter is supplied with a set of eight drop in gelatine filters in addition to the 340nmm interference filter and heated cuvette holder.  Each unit is thereby supplied capable of performing colorimetric tests across the visible wavelength spectrum and the near UV region

Quick Absorbance and Transmission measurements, Concentration with Standard Solutions or Factors, and Kinetic Reaction Rate and End Point methods are all possible. 

The Model 260UV Colorimeters can be supplied with a battery lead allowing utilisation of the colorimeter in situations where the only power source may be a vehicle battery

more about Sherwood Scientific’s M260UV CHROMA Colorimeter

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