Open AccessStructural Studies of a Polypeptide that Stimulates RNA Synthesis: A Component Obtained from Red Kidney Beans, the Source of Phytohemagglutinins
Author(s) -
HARMSRINGDAHL Mats,
JÖRNVALL Hans
Publication year - 1974
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1974.tb03795.x
Subject(s) - amino acid , rna , cysteine , peptide , biochemistry , yield (engineering) , chemistry , in vitro , composition (language) , kidney , spleen , peptide sequence , fraction (chemistry) , biology , chromatography , enzyme , gene , immunology , materials science , linguistics , philosophy , metallurgy , endocrinology
The amino‐acid composition of a polypeptide fraction that contains a few closely related polypeptides was determined. these polypeptides are obtained in high yield from red kidney beans and stimulate RNA synthesis in a bacterial system and in mouse spleen lymphocytes. Peptide maps of the carboxymethylated fraction were prepared and tryptic peptides purified and analysed for total composition and amino acid sequence. The results revealed that the differences between the polypeptides are due to a few microheterogeneities in the form of amino acid exchanges, but no evidence for the existence of polypeptides of different size or overall structure were obtained. It is concluded that the purification method yields different types of highly similar polypeptides with a molecular weight in the range of 10000, corresponding to about 80 residues, and an unusually high cysteine content of 19 mol/100 mol. These facts show that the present polypeptides are different from all previously analysed factors stimulating RNA synthesis.