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INHIBITION OF DIHYDROFOLATE REDUCTASE BY PALMITOYL‐CoA AND THE REVERSAL OF THE INHIBITION BY SPERMINE AND SPERMIDINE IN THE EGGS OF THE SEA URCHIN, HEMICENTROTUS PULCHERRIMUS *
Author(s) -
KUSUNOKI SHINICHIRO,
YASUMASU IKUO
Publication year - 1980
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.1980.00299.x
Subject(s) - hemicentrotus , spermine , dihydrofolate reductase , spermidine , putrescine , polyamine , sea urchin , aminopterin , biology , biochemistry , enzyme , microbiology and biotechnology , methotrexate , immunology
Dihydrofolate reductase activity in fertilized eggs of the sea urchin, Hemicentrotus pulcherrimus , was almost the same as in unfertilized eggs. Aminopterin inhibited the enzyme competitively with dihydrofolate (FH 2 ). The apparent K m value for FH 2 in the dihydrofolate reductase reaction was about 0.1 μM in the crude homogenate of both unfertilized and fertilized eggs. Dihydrofolate reductase in the eggs was also inhibited by palmitoyl‐CoA. The inhibition was canceled by polyamines, especially by spermine, but putrescine failed to prevent the enzyme from the inhibition. The change in long‐chain acyl‐CoA and polyamine concentrations during fertilization are discussed as possible regulatory factors of the enzyme.