| 释义 |
co-ˈfactor
1. Algebra. One of the several factors of a product; a coefficient.
2. Chem.
a. Any substance other than the substrate (as a co-enzyme or a metal ion) the presence of which is necessary for the activity of a particular enzyme.
b. (See quot. 1956.) (Formerly called co-enzyme factor.)
[1937Dewan & Green in Nature 25 Dec. 1098/1 A New Oxidation Catalyst... We have succeeded in resolving the so-called coenzyme oxidase into three insoluble components, (1) the coenzyme factor... The coenzyme factor catalyses the first oxidation.] 1945Jrnl. Cellular & Comparative Physiol. XXV. 12 The virus T4..is not effective in lysing such irradiated cells unless a co-factor such as tryptophane is present in the mixture to enhance its rate of adsorption on the host. 1949Advances in Enzymol. IX. 178 Certain ‘cofactors’, such as l-tryptophan, have the power of promoting adsorption of certain bacteriophages on their hosts. 1956New Gould Med. Dict. (ed. 2) 265/2 Cofactor, in bacteriology, any amino acid which must be present in the medium to activate phage to adsorb host bacteria. 1958Dixon & Webb Enzymes ix. 394 An additional substance besides the enzyme and substrate is required in many cases in order that the reaction may proceed. Such ‘cofactors’ are found unchanged at the end of the reaction and may therefore be regarded as an essential part of the catalytic mechanism. The majority of enzyme cofactors may be broadly divided into..(a) specific coenzymes..(b) activators. |