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THE DIAPAUSE FACTOR FROM THE SILKWORM, BOMBYX MORI L.: PURIFICATION AND INACTIVATION EXPERIMENTS
Author(s) -
SONOBE HARUYUKI
Publication year - 1974
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1111/j.1440-169x.1974.00147.x
Subject(s) - sephadex , isoelectric point , chromatography , size exclusion chromatography , trypsin , isoelectric focusing , pronase , incubation , chemistry , bombyx mori , biochemistry , chymotrypsin , cyanogen bromide , molecular mass , enzyme , peptide sequence , gene
The diapause factor, which is responsible for the induction of èmbryonic dia pause in the silkworm ( Bombyx mori L.), has been partially purified from the extract of adult heads by means of protein purification procedures, including the use of gel filtration of Sephadex, column chromatography on Dowex 1, isoelectric focusing and phenol extraction. Two species of the diapause factor could be recognized in respect to their molecular weight. They were separated by Sephadex G‐25 and their molecular weights were estimated to be about 2,000 and 5,000 from the gel filtration results. The smaller species was purified about 90‐fold in specific activity, and its isoelectric point was determined by isoelectric focusing to be at about pH 4.5. The biological activity of the partially purified principle could be abolished by incubation with several proteolytic enzymes (trypsin, α‐chymotrypsin and pronase), or by treatment with amino acid‐modifying reagents such as tyrosinase, N‐bromosuccinimide or 2‐hydroxy‐5‐nitrobenzyl bromide, but was not affected by incubation with neuraminidase, cyanogen bromide or photooxidation in the presence of methylene blue.