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Direct photolabeling with ( sup 32 P)UDP-glucose for identification of a subunit of cotton fiber callose synthase. [Gossypium hirsutum]

Journal Article · · Plant Physiology; (United States)
DOI:https://doi.org/10.1104/pp.95.2.556· OSTI ID:6056828
The authors have identified a 52 kilodalton polypeptide as being a likely candidate for the catalytic subunit of the UDP-glucose: (1{r arrow}3)-{beta}-glucan (callose) synthase of developing fibers of Gossypium hirsutum (cotton). Such a polypeptide migrates coincident with callose synthase during glycerol gradient centrifugation in the presence of EDTA, and can be directly photolabeled with the radioactive substrate, {alpha}-({sup 32}P)UDP-glucose. Interaction with the labeled probe requires Ca{sup 2+}, a specific activator of callose synthase which is known to lower the K{sub m} of higher plant callose synthases for the substrate UDP-glucose. Using this probe and several other related ones, several other proteins which interact with UDP-glucose were also identified, but none satisfied all of the above criteria for being components of the callose synthase.
DOE Contract Number:
AC02-76ER01338
OSTI ID:
6056828
Journal Information:
Plant Physiology; (United States), Journal Name: Plant Physiology; (United States) Vol. 95:2; ISSN 0032-0889; ISSN PLPHA
Country of Publication:
United States
Language:
English