The absence of a biuret reaction would point in that direction and the question must await further study.
This solution contains some protein or protein derivatives as it gives a very faint Millon reaction, a good positive ninhydrin test, reddish blue in color, but no biuret reaction.
It should be emphasized, however, that the Millon reaction was very faint, although the ninhydrin was quite marked and the biuret negative.
Biuret reaction (caustic potash and traces of sulphate of copper).
The decomposition products are generally the same as with the general albumin; it gives the biuret reaction; forms salts with acids and alkalies, but is essentially acid in nature.
They give the biuretand xanthoproteic reactions, and form salts with both acids and bases.
Here, however, on testing the filtrate from the ammonium sulphate-precipitate, a strong biuret reaction was obtained, thus proving the presence of at least some unaltered peptone.
The filtrate, on being tested with cupric sulphate and potassium hydroxide, gave a fairly strong biuret reaction for peptone.
Certainly, the latter shows no diminution in the strength of the biuret reaction after long contact at body temperature with such an extract.
On now testing a portion of the clear filtrate for peptone by the biuret test, not a trace of a reaction could be obtained.
Inasmuch as most natural proteins contain several such groups, the biuret reaction is a very general test for proteins.
Color reactions to which most of the common plant proteins respond are the following ones: (a) Biuret Reaction.
Peptones--products of further hydrolysis soluble in water, not coagulated by heat, not precipitated by ammonium sulfate, give biuret reaction.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "biuret" in a variety of sentences. We hope that you will now be able to make sentences using this word.
