User 4bd4d87d10

12-01-2012 21:15:39

I have used Marvin, Calculator Plugin and

Chemical Terms Demo to calculate LogP and LogD for a number of compounds that I

am studying and I have a technical question regarding calculation of these

parameters. LogP is the ratio of concentrations of a compound in the two phases

of a mixture of two immiscible solvents at equilibrium; typically one of then

solvent is water while the second is octanol. This true when a practical

experiment is carried out, but what about the mathematical model used by your

software? Is it is still true that this LogP expresses affinity to water or

octanol? In literature there are some examples of LogP (established

practically) in water/ hydrocarbons, so I wonder which hydrophobic phase is

taken into account by your software. The same question goes for LogD, is

octanol considered as the hydrophobic phase in your calculation?

Also, I have another question in relation to the

size/type of molecules and calculation of logP/ logD by your software. I wanted

to calculate the logP value for a decapeptide (slightly alkaline properties as

a free base) and the calculated values obtained with your software and another

programme differed significantly, although in both cases the molecule was shown

to be hydrophobic. I was wondering if your software has any limitations to

calculate the logP value of relatively simple peptides and proteins? Obviously

these are not simple organic compounds any more, is the calculation of logP

applicable for these cases? Thanks you very much in advance for clarification.

ChemAxon afdac7b783

13-01-2012 06:47:49

Yes, both logP and logD calculations considers octanol as the hydrocarbon phase, i.e., Partitioning plugin calculates the octanol/water partition and distribution coefficients.

The calculation method is based on the publication of Viswanadhan, V. N.; Ghose, A. K.; Revankar, G. R.; Robins, R. K., J. Chem. Inf. Comput. Sci., 1989, 29, 163-172, but the referred algorithm was modified at several points.

You can read more about our Patritioning plugin here: http://www.chemaxon.com/marvin/help/calculations/partitioning.html

/>The logP and logD calculation background can be found here: http://www.chemaxon.com/marvin/help/calculations/logPlogD.html

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To calculate the logP value, our software has no molecule size limitations.

Our logP and logD calculations were developed for small/drug molecules, that is the calculation results for peptides and proteins are not reliable by our method; however, logP plugin can be trained with your own (e.g., experimental) data to make a more precise calculation possible.

Find the training of logP and logD here: http://www.chemaxon.com/marvin/help/calculations/logp_training.html

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Best Regards,

Viktoria

User 3b514a39f6

16-11-2016 15:26:16

I am using JChem for excel and I am trying to calculate LogP/LogD for list of compounds. I can insert Jchem function in an excel cell. IN the insert funsert box, it shows LogP for selected compound but when I actually insert it in the cell, it only shows formula not the calculated value of LogP.

How do I see value LogP for list of compounds?

ChemAxon def2724101

17-11-2016 12:39:52

Dear Mihir,

An example how to display logP values for a list of compound in Excel:

The structures can be found in the column A of an Excel sheet and you would like to see the logP values in the column B next to the structures.

Please select the B1 cell and enter =JClogP(A1) into the B1 cell and press enter

>> the logP value (calculated for the structure in A1 cell) should be displayed in the B1 cell

Click on the bottom-right corner of the B1 cell, and copy the logP function from B1 cell to the B2, B3, B4, B5...... cells by dragging.

>> logP values - calculated for the structures in A2, A3, A4, A5 ... cells - should be displayed in B2, B3, B4, B5...... cells

Of course you can insert the JClogP function into the B1 cell by using the "Insert Function" function of the Excel.

In this case you have to select the JClogP function from the JChem_Protonation and Partitioning category on the Insert Function form.

Press OK and enter A1 as Molecule on the Function Arguments form and Press OK on the Function Arguments form

>> The calculated logP value should be displayed in B1 cell. You can copy the function into B2, B2, B3 cells by dragging.

Best regards,

Zsolt

ChemAxon def2724101

17-11-2016 13:01:17

Dear Mihir,

just an additional thing to my previous post regarding the JClogP function:

Please make sure that the cell format is "General" for the cells where you would like to see the calculated logP values. The General is the default cell format.

You can see the "JClogP(A1)" in the cell instead of the calculated logP values if the cell format is set to "Text".

You can check the cell format in the following way:

Select the cell

Make a right mouse-click

Select the Format Cells context menu item

>> On the first tab of the Format Cells form you can see the actual cell format. Of course you can change the cell format here.

Best regards,

Zsolt