Abstract
Sorghum bicolor stems and shoots were observed to phosphorylate exogenously supplied shikimate, forming a product which could not be distinguished from shikimate 3-phosphate by anion exchange and thin layer chromatography. Upon treatment with phosphatase, this product gave rise to a compound which co-chromatographed with shikimate.Shikimate kinase from stems was separated from phosphatase and ATPase and partially characterized. The stoichiometry of the reaction required equimolar quantities of ATP and shikimate to produce ADP and shikimate 3-phosphate. Maximal enzymic activity was observed near pH 9 in the presence of 11 millimolar MgCl(2). Graphs of reaction velocity as a function of substrate concentration were hyperbolic for both substrates and K(m) values of 0.2 and 0.11 millimolar were calculated for shikimate and ATP, respectively. Shikimate kinase was not inhibited by phenylalanine, tyrosine, or tryptophan, either alone or in combination. Slight inhibition was caused by p-coumarate and greater inhibition by caffeate. Inhibition was also observed in the presence of ADP and AMP, but the reaction velocity was not highly responsive to adenylate "energy charge" in experiments with ADP-ATP mixtures.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
