SEIBUTSU BUTSURI KAGAKU

A glycopeptide was isolated from tryptic digest of human stomach cancer tissue by preparative zone electrophoresis in a Pevikon C-870 block was used.
The results have been discussed and summarized as follows.
1. The glycopeptide, which migrated toward the anode slower than hyaluronic acid and was stained with alcian blue, was absent or sparingly present in the normal tissue, whereas it was found to a noticeable extent in the cancer tissue.
2. It possessed hexose, glucosamine and galactosamine as the major carbohydrate components, and also the abundance of threonine in the peptide moiety.

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Human serum albumin exposed to high pH's for various periods (usually 5min. -6hr.) in the temperature range 5-50°C were analyzed mainly by acrylamide gel electrophoresis at pH9.0. At the initial step of the alkaline denaturation, 8-9 discrete zones corresponding to components 1, 1', 2'', 2', 2, 3, 4, 5, and 6 appeared in the gel pattern. Components 1 and 1' are monomers, components 2'', 2', and 2 are dimers, and components 3-6 are further polymers of the albumin. At the next step gross aggregates which cannot penetrate the gel pore were formed, followed by the appearance of tailing in the gel pattern. When the denaturation proceeded further, the pattern was stained evenly and strongly, and gave no discrete zones, except for the zone 1'.
It was found that the initial step of the denaturation was composed of the following two reactions: In the first place, the intermolecular SH-S-S exchange reaction occurs between expanded human serum albumin molecules (component 1), and components 2'', 2', and 2 are produced successively (the “first reaction”). After component 2 attained reasonable amounts, thee component 1' is formed from the expanded albumin molecule (component 1) through the intramolecular SH-S-S exchange reaction, leading to the successive formation of components 2, 3, 4, 5, and 6 (the “second reaction”). It was observed that the decrease of the component 1 at the initial step followed the first-order kinetics.
The effects of cysteine and anti-denaturant were also studied.

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