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Physical & Chemical properties

Melting point / freezing point

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Reference
Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28-Mar-2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Justification for type of information:
Enzymes are polymers of 20 different naturally occurring amino acids in various length and order. The amino acids sequence determines the structure of the enzyme since at biological conditions the structure of this polymer is defined by the energy minimum fold. The enzyme fold and structure is held together primarily by hydrogen bonds, hydrophobic interactions, ion bonds and van der Waals forces between the different amino acids and cofactors. When heating the enzymes above the biological conditions, typically 80°C and higher, the attracting forces within the enzymes are broken, the fold is disrupted and the enzyme denatures. Denatured the enzymes lose their activity and typically coagulate. Thus a classical melting point is not relevant for enzymes.
Qualifier:
according to
Guideline:
other: Accredited methods of the analyzing laboratory have been evaluated by the national accreditation body of the country in question.
GLP compliance:
not specified
Type of method:
other: Accredited methods of the analyzing laboratory have been evaluated by the national accreditation body of the country in question (Finland)
Decomposition:
yes
Remarks:
At the decomposition temperature the sample starts to decompose, caramelize and blacken (like ash).
Decomp. temp.:
180 °C

The sample did not melt, but remained black between 180 - 300 °C.

Description of key information

No melting point, sample decomposition commenced at 180 °C.

Key value for chemical safety assessment

Additional information

Between 180 - 300 °C the sample decomposed, caramelized and blackened (like ash).