Purification and Properties of Soluble and Bound γ-Glutamyltransferases from Radish Cotyledon
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Soluble and cell wall bound γ-glutamyltransferases (GGTs) were purified from radish (<I>Raphanus sativus</I> L.) cotyledons. Soluble GGTs (GGT I and II) had the same <I>M</I><SUB>r</SUB> of 63,000, and were composed of a heavy subunit (<I>M</I><SUB>r</SUB>, 42,000) and a light one (<I>M</I><SUB>r</SUB>, 21,000). The properties of GGT I and II were similar. Bound GGTs (GGT A and B) were purified to homogeneity from the pellet after the extraction of soluble GGTs. GGT A and B were monomeric proteins with an <I>M</I><SUB>r</SUB> of 61,000. The properties of GGT A and B were similar. Thus, bound GGTs were distinguished from soluble GGTs. The optimal pHs of soluble and bound GGTs were about 7.5. Both soluble and bound GGTs utilized glutathione, γ-<small>L</small>-glutamyl-<I>p</I>-nitroanilide, oxidized glutathione and the conjugate of glutathione with monobromobimane as substrates, and were inhibited by acivicin, but soluble GGTs were also distinguished from bound GGTs with regard to these properties.
- Agricultural and Biological Chemistry
Agricultural and Biological Chemistry 70(2), 369-376, 2006-02-23
Japan Society for Bioscience, Biotechnology, and Agrochemistry