Tryspin and film

[Krysia Lee]

Arhhh the teachers away and the girls are asking what concentration of trypsin to use on film to make it go clear. Anyone heard of this?

[mtg]

I have Trypsin - "to hydrolyse casein-food chem" it's from pancreas.????

[nickykinz]

Sorry can't help with the actual question but I was wondering why does this post have a little exlamation mark next to it?

[smiley]

We're not supposed to put web links up here, but check out the "Nuffield Foundation" - they have this prac written up there. The concentration is 5% Trypsin, as a standard, and then I think the little cherubs can dilute it to see the changes in time taken.

[Krysia Lee]

Thanks Smiley
that is the actual prac we are doing but there is no result on the film and I wonder if we need higher concentrations of trypsin. In which case we're shot ducks because we're out of trypsin. Have tried varying the temp as well. I put the exclaimation mark there because I was in a hurry in the middle of the prac. We're resorting to the pineapple juice and gelatin prac. There is a group fifteen girls and they are all doing something different

[nickykinz]

Oh, does it mean urgent? I thought it meant someone had reported it as that what the "report this post" thing looks like. Sorry, makes sense now.
Monday morning! Haven't woken up yet.

[Jazz]

if we can not post link than
Aim

To investigate the effect of temperature on the activity of trypsin - using casein as the substrate.

Materials and method

A water bath was heated to 25°C. 5cm³ of 4% casein solution was put into one test tube and 5cm³ of 0.5% trypsin was added to another test tube. Both were stood in a water bath until they reached the correct temperature. The same quantity of casein solution was added to another test tube and 5cm³ distilled water in a fourth test tube. This acted as a control. Another control consisted of
5cm³ distilled water in a fifth test tube and 5cm³ casein in a final test tube. All of these were also placed into the water bath. Black card was placed behind the test tubes to help spot the clearing of the solution. The enzyme and substrate were mixed, a stopwatch started immediately, and the time for the suspension to clear noted. This was repeated for the controls, and the whole experiment repeated for different temperatures, ranging from 25°C - 65°C.

Results and discussion
The control showed no change in colour at any temperature. In the graph below, we plotted the relative reaction rate (1/time taken to see a colour change) against the temperature. As the temperature increased, the time for a colour change to be seen was less (1/t was bigger). At a certain point, the relative reaction rate started decreasing. This was the optimum temperature (~ 37°C).

google this article