The best source for such a diaphorase is probably Asahi-Kasei (www.asahi-kasei.co.jp/shindan/eng/list/index.html). Their enzyme is claimed to be four times less reactive with NADPH than NADH.

There is constant pressure on IVD manufacturers to develop new diagnostic assays which deliver improved performance and accuracy, but which remain cost effective.

Enzyme suppliers can assist in this process by working with customers to develop superior products, for example with higher activity or in different formulations, which enable improved assay performance.

Tests for novel diagnostic markers may require the development of new enzymes. IVD manufacturers may wish to collaborate with enzyme suppliers that provide a custom development service.

Today’s diagnostic reagents use a wide range of both naturally derived and recombinant enzymes. In many cases the available natural enzymes provide appropriate performance at a reasonable cost, however where there is no natural enzyme readily available, or its performance is inadequate, then a recombinant enzyme is required.  The majority of natural enzymes already employed in diagnostic reagents have well managed supply chains and are manufactured to produce consistent  performance from lot to lot, so it is unlikely that they would be need to be replaced by recombinant enzymes. The use of recombinant enzymes is likely to increase therefore,  due to the demand for 1/ particular improved performance criteria in existing reagents or 2/ the measurement of new analytes requiring the development of novel enzymes.

The pricing of today’s recombinant enzymes is largely driven by the scale of the fermentation hence if the demand volumes increase then there should be a concomitant decrease in pricing. Aside from volume, technical advances such as optimised vectors producing increased expression levels, greater control of protein folding and glycosylation levels, and the secretion or compartmentalising of functional enzymes to make harvesting easier should all combine to drive down the costs of production. However enzyme manufacturers will have to account for substantial research & development costs to overcome such technical hurdles so while a significant reduction in the pricing of recombinant enzymes is on the horizon it is unlikely to take place in the near future.

Quality is key for manufacturers looking to source enzymes for use in diagnostic assays. Suppliers should be able to meet the required industry quality standards, for example ISO 9001:2008. Furthermore, for existing products, documentation such as Certificates of Analysis and Material Safety Data Sheets, along with product specifications and where appropriate veterinary certificates should be readily available.

Experience of supply into market is also a must. Working with a supplier who understands the demands of IVD manufacturers and already supplies products with proven performance leads to fewer supply chain issues.

One size doesn’t fit all. A supplier should be flexible and have the capability to work with IVD manufacturers to develop bespoke products, along with customised analytical testing procedures.

Once you have found such a supplier, you want to know that they will prove to be reliable. Continuous supply and short lead times are critical. Ensure you are comfortable with their capacity and ability to source vital raw materials.