6 replies to this topic

[tnoni]

Hello,

New to the community but was hoping I could get some help. I'm not really a whiz with this stuff and I'm trying to recreate an experiment.

I have a collagenase with an activity of ~125 units per mg solid.

In the experiment they used the same collagenase but obtained a 427 U/mg solid and created a 1000 U/ml collagenase solution and incubated at 37 C at a pH of 7.5.

Could anyone help me produce the same solution? I've been doing some reading but have been awfully confused. Any help would be greatly appreciated.  

[mdfenko]

at ~125u/mg solid you require ~8mg solid (125*8=1000). adjust to 1ml with a pH7.5 buffer.

[tnoni]

mdfenko, on Mar 10 2010, 11:53 AM, said:

at ~125u/mg solid you require ~8mg solid (125*8=1000). adjust to 1ml with a pH7.5 buffer.

thanks for your help! is it safe to assume the 427 U/mg solid was not necessary information and just included in their experiment description? and i have a saline solution at pH 7.5 when you say adjust to 1 ml. am i just adding the 8mg solid to 1000 ml of the buffer?

sorry for all the questions. i really appreciate the help  

[mdfenko]

tnoni, on Mar 10 2010, 03:23 PM, said:

thanks for your help! is it safe to assume the 427 U/mg solid was not necessary information and just included in their experiment description? and i have a saline solution at pH 7.5 when you say adjust to 1 ml. am i just adding the 8mg solid to 1000 ml(?) of the buffer?

the statement is telling you the specific activity of the material they used, it is an indicator of purity. yours is less pure than theirs. will the additional impurities make a difference? you'll have to be the judge of that.

just add the ml to the 8mg solid (technically you should add buffer until the volume is 1ml but 8mg should not add significant volume, at least not more than the error from the pipet will).

[tnoni]

mdfenko, on Mar 10 2010, 01:31 PM, said:

tnoni, on Mar 10 2010, 03:23 PM, said:

thanks for your help! is it safe to assume the 427 U/mg solid was not necessary information and just included in their experiment description? and i have a saline solution at pH 7.5 when you say adjust to 1 ml. am i just adding the 8mg solid to 1000 ml(?) of the buffer?

the statement is telling you the specific activity of the material they used, it is an indicator of purity. yours is less pure than theirs. will the additional impurities make a difference? you'll have to be the judge of that.

just add the ml to the 8mg solid (technically you should add buffer until the volume is 1ml but 8mg should not add significant volume, at least not more than the error from the pipet will).

you've been a great help. thanks so much

[HomeBrew]

There might be some confusion here, tnoni -- mdfenko is telling you to dissolve 8 mg in a total volume of 1 ml to make 1 ml of a 1000 U/ml solution, which in your case is also an 8 mg/ml solution.  If you need to make a liter of the solution, you'll need 8 grams (8 mg x 1000) dissolved in a final volume of one liter...

[tnoni]

HomeBrew, on Mar 10 2010, 08:04 PM, said:

There might be some confusion here, tnoni -- mdfenko is telling you to dissolve 8 mg in a total volume of 1 ml to make 1 ml of a 1000 U/ml solution, which in your case is also an 8 mg/ml solution.  If you need to make a liter of the solution, you'll need 8 grams (8 mg x 1000) dissolved in a final volume of one liter...

ah i get it now. thanks for the clarification. i would have looked silly