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HEPATIC PROTEIN LOCATED BY THE OXIDIZED TANNIN‐AZO METHOD
Author(s) -
Dixon Kendal C.
Publication year - 1962
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1962.sp001567
Subject(s) - tannin , tannic acid , deamination , chemistry , amino acid , biochemistry , organic chemistry , food science , enzyme
The oxidized tannin‐azo (OTA) method was used to study the location of tannophilic protein in hepatic cells. In this method tannic acid was first attached to the tissue proteins and then oxidized with periodic acid; the oxidized tannin, which was firmly bound to the cellular proteins, was subsequently converted to a highly coloured azo dye by coupling with diazotized o‐dianisidine. Preliminary deamination with nitrous acid markedly diminished the capacity of hepatic cells to stain with OTA; this indicates that ‐NH 3 groups in the tissue proteins are the principal loci revealed by the OTA method. Sections of liver, after tanning and oxidation, were also treated with 6‐amino‐3‐dimethylaminophenol; this technique produced intense colouration of the hepatic cells probably owing to the formation of an oxazine dye. The colouration of oxidized tannin by 6‐amino‐3‐dimethylaminophenol confirms the view that bound tannin is oxidized by periodic acid to a 1–2‐quinone.