Esterase, cholesterol

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 August 2013 - 19 Dec 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Certificate included in report

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Test material

Test material information

Constituent 1

Reference substance name:

Lipase, triacylglycerol

EC Number:

232-619-9

EC Name:

Lipase, triacylglycerol

Cas Number:

9001-62-1

Molecular formula:

Not available. See Remarks.

IUPAC Name:

Triacylglycerol lipase IUBMB 3.1.1.3

Test material form:

liquid

Details on test material:

- Substance type: UVCB
- Physical state: Liquid
- Lot/batch No.: 3606K16
- Expiration date of the lot/batch: Sep 2015
- Storage condition of test material: Minus 20 degrees of C

Study design

Analytical method:

other: UV/VIS spectroscopy

Results and discussion

Partition coefficient

Key result

Type:

log Pow

Partition coefficient:

-1.93

Temp.:

20 °C

pH:

>= 6.5 - <= 7

Details on results:

The detector calibration was found to be linear over the range 0 to 1440 mg/L of standard solutions in water with a regression coefficient of 1.0000.
It had been anticipated that the test substance would not partition into the n-octanol phase and therefore the full scale spectra of the organic phases were assessed in order to verify that the absorbance was due to the enzyme. A typical spectrum is presented in the report and confirms the identity of the material in the n-octanol as lipase.
It was proposed that a reason for the presence of lipase in the n-octanol phases was due to water dissolved in the n-octanol causing the compound to occur in the organic phase. It was therefore regarded that the determined partition coefficient value represented a maximum value and the true partition coefficient was probably lower.
The accuracy of the analytical method was verified by the analysis of five replicate samples prepared at two concentrations: one at the level analysed for the aqueous phases (approximately 1200 mg/L) and one at a level equivalent to a nominal limit of quantification (approximately 21 mg/L). The recoveries were 102% and 85%, respectively, and served to demonstrate the accuracy of the method.

Applicant's summary and conclusion

Conclusions:

The octanol/water partition coefficient of lipase was found to be < 0.01 (log10 Pow = < -1.9) at 20°C.

Executive summary:

A study was performed to determine the partition coefficient of the test substance, lipase, according to EEC Method A8 and OECD Method 107.

The study was conducted to comply with the requirements of European Council Directive for 91/414/EEC (Annex II) as amended by European Commission Directive 94/37/EC and amended by Commission Regulation (EU) No. 544/2011 Implementing Regulation (EC) Nov 1107/2009 of the European Parliament and of the Council as regards the data requirements for active substances.

The octanol/water partition coefficient of lipase was found to be < 0.01 (log10 Pow = < -1.9).