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Contractions accompanying the swelling of gelatin in solutions of varying pH

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Field Value
Title Contractions accompanying the swelling of gelatin in solutions of varying pH
Names Brown, Betty (creator)
Friedman, Leo (advisor)
Date Issued 1934-05-24 (iso8601)
Note Graduation date: 1934
Abstract There are two distinct methods which are used to study
the volume changes which take place when a protein is placed
in a solution. The first and most common method measures the
volume changes of the solid alone and is commonly known as swelling. The second measures the total volume change which
takes place upon mixing the two components--that is, the volume
of the solution plus the volume of the solid protein
minus the volume of the resulting system. The results of the first method have been thought to indicate the degree of
water absorption, while the second supposedly indicates the
degree of hydration.
A knowledge of the latter might possibly lead to a better
understanding of the processes of the former, and, consequently,
to a better understanding of the phenomenon of swelling.
Up to the present time, very few measurements have been
made on the total volume changes occurring during the swelling
of proteins, and the results which have been published do
not substantiate each other. Therefore a study of the volume
changes accompanying the swelling of gelatin in solutions of
varying hydrogen ion concentration has been made in an
attempt to correct and correlate the data already present
in the literature.
Measurements have been made to determine the influence
of pH on the contractions accompanying the swelling of gelatin. It was found that a definite minimum in contraction
occurred at the isoelectric point, the contraction increasing
with increase or decrease in the hydrogen ion concentration. The maximum and minimum in the contraction
curve below the isoelectric point occurs at a pH corresponding
to the maximum and minimum in the swelIing curve
given by Loeb. The maximum on the basic side is shifted
toward the isoelectric point. No second minimum occurs at the higher pH values.
The contraction-time curve has the same general shape
as an absorption-velocity curve. When the contraction per
gram of water imbibed is plotted against the time a straight
line is obtained. The results indicate that the contraction
per gram of the original gel is independent of the amount of
gelatin used.
Genre Thesis/Dissertation
Topic Proteins
Identifier http://hdl.handle.net/1957/51720

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