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Action of pepsin on egg white

It is essential to check effectiveness of acidified pepsin/egg white mixture before the experiment; concentrations of acid & enzyme could be adjusted to bring conversion time to a reasonable value
Optimum treatment (2.0 ml acid, 3.0ml pepsin, 10ml egg white suspension) should have pH about 2, and show complete clearing after about 5 minutes.

Shopping: 1/2 doz cheap eggs
(Make up egg white solution the day before experiment)


36C water bath
Hydrochloric acid 0.25M in dropping bottles
Universal indicator paper
Safety spectacles


1 egg white whisked into 400cm3 of boiling water and sieved. (May need to double the quantities depending on number of groups) 75cm3 per group

2% pepsin 15cm3 per group

1% amylase

Biuret solution or 1% Copper Sulphate + Sodium Hydroxide solution