Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
water solubility
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING

The degree of solubility at a given pH depends on several factors, e.g. temperature, the amino acid sequence and structure of the enzyme and other components in the system such as salts. The amino acid sequence and structure affect the polarity, including the isoelectric point (pI) of the enzyme, which is an important factor for solubility. The difference in solubility is thus a reflection of the variation in the amino acid sequence. Also, post translational modifications influence the solubility, where the most important is glycosylation that typically increases the solubility. The solubility of another enzyme, B-glucosidase, in purified water at pH 7 is between 0,5 and 250 g/l.

The influence of pH and salt concentration on protein stability has been investigated in the following publications; Carbonnaux et al., 1995; Green, 1932; Guilloteau et al., 1992; Hofmeister 1888. In a more recent study, the solubility of alpha-amylases is described (Faber, 2006). The alpha-amylases investigated here had pI of 5.5-6.1 and showed an increase in solubility with increasing pH when analyzed for in the pH range 6 to 10. The study shows a ten to hundredfold increase in solubility at pH 10 compared to pH 6 (Faber 2006). The effects of anions and cations on protein solubility in general are described by the Hofmeister series (Hofmeister 1888). The above indicate that the solubility of proteins like enzymes is dependent on the conditions for a given environment. Enzymes generally have the lowest solubility when the pH is close to pI (+/- 1 pH unit) and the solubility increases when pH is shifting away from pI, as long as the pH is not denaturing the enzyme. The pI of beta-glucosidases ranges from 3 to 8.55 (http://www.brenda-enzymes.info/).

The conclusion is that the water solubility differs between different enzymes, due to difference in amino acid sequence and presence of post translational modifications. Water solubility is also highly dependent on the aqueous environment, i.e. pH, salts present, temperature and stabilizing agents, and it is thus not possible to give one water solubility value for all industrial produced enzymes but only a range. Industrial enzymes are produced in submerged fermentation followed by downstream purification. The final product is a mixture of the enzyme, impurities from the fermentation and stabilizing agents that are added in the downstream processing. In general, solubility data are based either on finished products or enzymes purified in buffer and salts and not in purified water alone.

References:
Carbonnaux, C., Riès-Kautt, M., & Ducruix, A., (1995); Protein Science, 4, 2123 -2128.
Green, A. A., (1932); Physical Chemistry of Proteins, 10, 47-66.
Guilloteau, J. P., Riès-Kautt, M., & Ducruix, A., (1992); Journal of Crystal Growth, 122, 223-230.
Hofmeister, F., (1888); Archiv für experimentelle Pathologie und Pharmakologie, 24, 247 -260.
Cornelius Faber, Timothy J. Hobley, Jørgen Mollerup, Owen R. T. Thomas and Svend G. Kaasgaard (2007); 'Study of the Solubility of a Modified Bacillus licheniformis r-Amylase around the Isoelectric Point', J. Chem. Eng. Data, 52, 707-713

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion