Nitrile hydratase recombinant from E.coli

Flammability

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

flammable solids

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Reference 2

Endpoint:

pyrophoric liquids

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

As the enzymes are proteins produced by fermentations, i.e. usually in solution, enzymes are not pyrophoric. In the pure, lyophilised form, they might be pyrophoric, but will in such case only exist in very small quantities for research purpose. It is therefore considered justified to waive this endpoint. 

Reference 3

Endpoint:

substances / mixtures which in contact with water emit flammable gases

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the experience in production or handling shows that the substance does not react with water, e.g. the substance is manufactured with water or washed with water

Justification for type of information:

In accordance with point 1 of Annex XI, it is considered justified to omit the testing for substances or mixtures which in contact with water emit flammable gases. Enzymes are easily soluble in water and from experience of handling enzymes together with consideration of the structure of enzymes it can be concluded that enzymes are not flammable on contact with water.

Description of key information

Flammability (solids)

In accordance with REACH Annex XI, section 2, a flammability (solids) study is not required as testing is technically not possible as a consequence of the properties of the substance.

The substance, nitrile hydratase, is a substance that is handled in a state where a mixture of the enzyme and the dead bacteria that produced it is dispersed in water.

A fundamental requirement for testing the physicochemical properties of a substance, is that the substance is tested as such, excluding all solvents. However, since the higher order structure of the constituent molecules of the proposed substance (nitrile hydratase) is damaged by the removal of water, it cannot be said that the proposed substance would be correctly evaluated by performing this test after the removal of water. It should therefore be avoided.

In order to avoid deterioration it would be possible to conduct the test by leaving the substance as a suspension (ie dispersed in water). However, to do so would render the test results meaningless as the physical properties of water would greatly influence the results of such a test. As such, it would not be possible to consider the results of any such test as indicative of the physicochemical properties of the substance as such. The substance, nitrile hydratase, is a substance that is handled in a state where a mixture of the enzyme and the dead bacteria that produced it is dispersed in water. A fundamental requirement for testing the physicochemical properties of a substance, is that the substance is tested as such, excluding all solvents. However, since the higher order structure of the constituent molecules of the proposed substance (nitrile hydratase) is damaged by the removal of water, it cannot be said that the proposed substance would be correctly evaluated by performing this test after the removal of water. It should therefore be avoided. In order to avoid deterioration it would be possible to conduct the test by leaving the substance as a suspension (ie dispersed in water). However, to do so would render the test results meaningless as the physical properties of water would greatly influence the results of such a test. As such, it would not be possible to consider the results of any such test as indicative of the physicochemical properties of the substance as such. As such it is technically impossible to obtain a meaningful result.

 

Flammability (contact with water)

In accordance with point 1 of Annex XI, it is considered justified to omit the testing for substances or mixtures which in contact with water emit flammable gases. Enzymes are easily soluble in water and from experience of handling enzymes together with consideration of the structure of enzymes it can be concluded that enzymes are not flammable on contact with water.

 

Flammability (pyrophoricity)

As the enzymes are proteins produced by fermentations, i.e. usually in solution, enzymes are not pyrophoric. In the pure, lyophilised form, they might be pyrophoric, but will in such case only exist in very small quantities for research purpose. It is therefore considered justified to waive this endpoint. 

Key value for chemical safety assessment

Flammability:

not classified

Justification for classification or non-classification

In accordance with the criteria for classification as defined in Annex I, Regulation (EC) No 1272/2008, the substance does not require classification with respect to flammability.