Shikimate dehydrogenases

Figure 1. Schematic outline of various products and associated enzymes from the shikimate and phenolic pathways in plants (and some microorganisms). Enzymes (1) 3-deoxy-2-oxo-D-arabino-heptulosate-7-phosphate synthase (2) 5-dehydroquinate synthase (3) shikimate dehydrogenase (4) shikimate kinase (5) 5-enol-pyruvylshikimate-3-phosphate synthase (6) chorismate synthase (7) chorismate mutase (8) prephenate dehydrogenase (9) tyrosine aminotransferase (10) prephenate dehydratase (11) phenylalanine aminotransferase (12) anthranilate synthase (13) tryptophan synthase (14) phenylalanine ammonia-lyase (15) tyrosine ammonia-lyase and (16) polyphenol oxidase. (From ACS Symposium Series No. 181, 1982) (62).

ENZ enzyme assays, SC structural composition, MM molecular methods, IL isotopic labeling, IF isotopic fractionation, INH inhibition studies, UNK unknown, LOX lipoxogenase, EPSP synthase 5-enolpyruvylshikimate-3-phosphate, SDH shikimate dehydrogenase, PAL phenylalanine ammonium lyase, PKS polyketide synthase, NRPS nonribosomal peptide synthase 1 Gerwick 1999 2 Liu et al. 1994 3 Boonprab et al. 2003 4 Cvejic and Rohmer 1999 5 Disch et al. 1998 6 Chikaraishi et al. 2006 7 Schwender et al. 2001 8 Schwender et al. 1997 9 Mayes et al. 1993 10 Shick et al. 1999 11 Richards et al. 2006 12 Bouarab et al. 2004 13 Pelletreau et al., unpublished data 14 Dittman and Weigand 2006 15 Rein and Barrone 1999 Empty columns imply no direct evidence of these enzymes from these systems... 

SHIKIMATE DEHYDROGENASE SULFITE REDUCTASE VALINE DEHYDROGENASE ZEATIN aS-TRANS ISOMERASE NADPH DEHYDROGENASE NAD(P)H DEHYDROGENASE (QUINONE) NADPH-dependent enzymes, ACYL-ACYL-CARRIER-RROTEIN -DESA-TURASE... 

SHIKIMATE DEHYDROGENASE SHIKIMATE KINASE Shikimate 3-phosphate,... 

Enzyme Assays. Procedures for the HPLC assay of prephenate aminotransferase (32), the spectrophotometric assay of shikimate dehydrogenase... 

Shikimate dehydrogenase The use of modified buffer increased the specific activities (S.A.) of this enzyme in the soluble supernatant preparations about sixfold (from 3.0 to 20.3). In addition, activity not otherwise measured in the homogenized pellet was found there with the use of modified buffer. In modified buffer shikimate dehydrogenase activity (e.g.,... 

S.A. = 0.67 in octyl glucoside buffer) could be found in all of the detergent-extract preparations. As above, the hemoglobin step increased dramatically the S.A. of shikimate dehydrogenase assayed in detergent-extract preparations. 

A) DAHP synthase (B) DHQ synthase (C) DHQ dehydratase (D) shikimate dehydrogenase (E) quinate dehydrogenase (F) DHS dehydratase (G) protocatechuate decarboxylase (H) catechol 1,2-dioxygenase. 

Cole al. (72) found that glyphosate increased extracted specific activities of two shikimate pathway enzymes, shikimate dehydrogenase (shikimate NADP oxidoreductase. Figure 3, No. 

Plants contain shikimate dehydrogenase (shikimate NADP oxidoreduc-tase) which reversibly interconverts dehydroshikimate and shikimate [Fig. 2 (4)]. The enzyme has been detected in a number of plant sources (Balinsky and Davies, l%la Yoshida, 1969). Unlike the microbial enzyme which is specific for NAD, the plant enzyme is specific for NADP (Balinsky and Davies, 1961b). Anthranilic acid and hydroxybenzoic acids inhibit the reaction in the direction of shikimate dehydrogenation (Balinsky and Davies, 1961b). The significance of the inhibition in controlling the activity of the pathway is unknown. 

As many as five forms of shikimate dehydrogenase have been reported in Vida faba Feierabend and Brassel, 1977) up to four multiple forms of the enzyme have been detected in barley, and at least two forms exist in several other plants (Rothe, 1974). 

There is growing evidence that the shikimate pathway enzymes exist in the chloroplast as well as in the cytoplasm. Shikimate dehydrogenase isoen-... 

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