BIOSYNTHESIS OF THE COUMARINS. TRACER STUDIES ON COUMARIN FORMATION IN HIEROCHLOË ODORATA AND MELILOTUS OFFICINALIS

1960 ◽  
Vol 38 (1) ◽  
pp. 143-156 ◽  
Author(s):  
Stewart A. Brown ◽  
G. H. N. Towers ◽  
D. Wright

Coumarin formation has been studied with C14in the perennial grass, Hierochloë odorata, and in yellow sweet clover, Melilotus officinalis. In general the latter species yielded inconsistent data. In Hierochloë, o-coumaric, cinnamic, and shikimic acids and L-phenylalanine were the best of 10 compounds tested as coumarin precursors, the first two at least being incorporated with little randomization of C14. Acetate was more poorly utilized. It was concluded that the aromatic ring of coumarin arises via the shikimic acid pathway in preference to acetate condensation. When the time of metabolism was varied, o-coumaryl glucoside and free o-coumaric acid rapidly acquired high specific activities from cinnamic acid-C14, but coumarin and melilotic acid became active much more slowly. A lag in the acquisition of C14by coumarin for the first 6 to 8 hours was followed by a rectilinear increase until at least 24 hours. Much the greatest accumulation of C14was found in o-coumaryl glucoside during this entire period. Furthermore, this compound when fed to Hierochloë is comparable to cinnamic acid as a coumarin precursor. These findings suggest a possible function for o-coumaryl glucoside or a derivative in coumarin biosynthesis.

1960 ◽  
Vol 38 (2) ◽  
pp. 143-156 ◽  
Author(s):  
Stewart A. Brown ◽  
G. H. N. Towers ◽  
D. Wright

Coumarin formation has been studied with C14in the perennial grass, Hierochloë odorata, and in yellow sweet clover, Melilotus officinalis. In general the latter species yielded inconsistent data. In Hierochloë, o-coumaric, cinnamic, and shikimic acids and L-phenylalanine were the best of 10 compounds tested as coumarin precursors, the first two at least being incorporated with little randomization of C14. Acetate was more poorly utilized. It was concluded that the aromatic ring of coumarin arises via the shikimic acid pathway in preference to acetate condensation. When the time of metabolism was varied, o-coumaryl glucoside and free o-coumaric acid rapidly acquired high specific activities from cinnamic acid-C14, but coumarin and melilotic acid became active much more slowly. A lag in the acquisition of C14by coumarin for the first 6 to 8 hours was followed by a rectilinear increase until at least 24 hours. Much the greatest accumulation of C14was found in o-coumaryl glucoside during this entire period. Furthermore, this compound when fed to Hierochloë is comparable to cinnamic acid as a coumarin precursor. These findings suggest a possible function for o-coumaryl glucoside or a derivative in coumarin biosynthesis.


1959 ◽  
Vol 37 (1) ◽  
pp. 537-547 ◽  
Author(s):  
D. R. McCalla ◽  
A. C. Neish

p-Coumaric, caffeic, ferulic, and sinapic acids were found to occur in Salvia splendens Sello in alkali-labile compounds of unknown constitution. A number of C14-labelled compounds were administered to leafy cuttings of salvia and these phenolic acids were isolated after a metabolic period of several hours and their specific activities measured. Cinnamic acid, dihydrocinnamic acid, L-phenylalanine, and (−)-phenyllactic acid were found to be good precursors of the phenolic acids. D-Phenylalanine, L-tyrosine, and (+)-phenyllactic acid were poor precursors. A kinetic study of the formation of the phenolic acids from L-phenylalanine-C14 gave data consistent with the view that p-coumaric acid → caffeic acid → ferulic acid → sinapic acid, and that these compounds can act as intermediates in lignification. Feeding of C14-labelled members of this series showed that salvia could convert any one to a more complex member of the series but not so readily to a simpler member. Caffeic acid-β-C14 was obtained from salvia after the feeding of L-phenylalanine-β-C14 or cinnamic acid-β-C14, and caffeic acid labelled only in the ring was obtained after feeding generally labelled shikimic acid.


1959 ◽  
Vol 37 (4) ◽  
pp. 537-547 ◽  
Author(s):  
D. R. McCalla ◽  
A. C. Neish

p-Coumaric, caffeic, ferulic, and sinapic acids were found to occur in Salvia splendens Sello in alkali-labile compounds of unknown constitution. A number of C14-labelled compounds were administered to leafy cuttings of salvia and these phenolic acids were isolated after a metabolic period of several hours and their specific activities measured. Cinnamic acid, dihydrocinnamic acid, L-phenylalanine, and (−)-phenyllactic acid were found to be good precursors of the phenolic acids. D-Phenylalanine, L-tyrosine, and (+)-phenyllactic acid were poor precursors. A kinetic study of the formation of the phenolic acids from L-phenylalanine-C14 gave data consistent with the view that p-coumaric acid → caffeic acid → ferulic acid → sinapic acid, and that these compounds can act as intermediates in lignification. Feeding of C14-labelled members of this series showed that salvia could convert any one to a more complex member of the series but not so readily to a simpler member. Caffeic acid-β-C14 was obtained from salvia after the feeding of L-phenylalanine-β-C14 or cinnamic acid-β-C14, and caffeic acid labelled only in the ring was obtained after feeding generally labelled shikimic acid.


1993 ◽  
Vol 48 (11-12) ◽  
pp. 879-885 ◽  
Author(s):  
Fumiaki Tanigaki ◽  
Atsushi Ishihara ◽  
Kazuichi Yoshida ◽  
Takane Hara ◽  
Masateru Shinozaki ◽  
...  

n-Propyl N-(3,4-dichlorophenyl)carbamate, which induces flowering while it inhibits a step or steps in the phenylpropanoid metabolism in Asparagus officinalis L. seedlings, was found to retard the conversion of t-cinnamic acid to p-coumaric acid by high-pressure liquid chromatography of the metabolites in the shikimic acid pathway. The concentrations of the metabolites preceding t-cinnamic acid on the pathway in treated and untreated seedlings were the same, but those of p-coumaric acid and later metabolites were significantly lower in treated plants. The carbamate inhibited phenylpropanoid metabolism when used to treat stem segments that included a shoot apex primordium, where flowers are induced, and when added to a 100,000 × g microsomal fraction prepared from such segments. NADPH-cytochrome P-450 and NADH-cytochrome b5 reductases in the 100,000 × g fraction were not inhibited by the carbamate. The results showed that this compound has its site of action on the endoplasmic reticulum and that it inhibits cytochrome P-450s, including t-cinnamic acid 4-hydroxylase. We examined the flower-inducing activity of known cytochrome P-450 inhibitors, and found that piperonyl butoxide also causes flowering.


1959 ◽  
Vol 37 (5) ◽  
pp. 1085-1100 ◽  
Author(s):  
A. C. Neish

A number of C14-labelled compounds were fed to detached leafy twigs of Colorado spruce (Picea pungens Engelm.), and after a metabolic period of 24 hours the pungenin was isolated and the specified activities of the glucose moiety and the aglycone (3,4-dihydroxyacetophenone) were determined. In some instances the aglycone was degraded further to determine the C14 in the methyl and carbonyl carbons separately.Caffeic acid and L-phenylalanine were the best precursors of the aglycone; cinnamic acid, p-coumaric acid, phenyllactic acid, and shikimic acid were quite good. Sodium acetate was a poor precursor, and was converted to glucose more readily than to the aglycone. Compounds found to be very poor precursors include tyrosine, 3,4-dihydroxyphenylalanine, 3-hydroxytyramine, phenylacetic acid, mandelic acid, p-hydroxyphenylpyruvic acid, p-hydroxyphenyllactic acid, p-hydroxybenzoic acid, and protocatechuic acid. Cinnamic acid-α-C14 gave 3,4-dihydroxyacetophenone labelled chiefly in the methyl group, while cinnamic acid-β-C14, L-phenylalanine-β-C14, p-coumaric acid-β-C14, and caffeic acid-β-C14 formed 3,4-dihydroxyacetophenone labelled mainly in the carbonyl carbon. It appears that a phenylethanoid compound is formed by a process involving the loss of the terminal carbon of a phenylpropanoid compound.3,4-Dihydroxyacetophenone-carbonyl-C14 was fed to spruce twigs bearing new terminal growth; up to 20% was converted to pungenin but most of it formed unidentified compounds. It was a poor precursor of lignin, compared with cinnamic acid, and a poor precursor of glutamic acid, relative to acetate.


Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1263
Author(s):  
Chun-Yen Hsieh ◽  
Yi-Hao Huang ◽  
Hui-Hsuan Yeh ◽  
Pei-Yu Hong ◽  
Che-Jen Hsiao ◽  
...  

Phenylalanine ammonia-lyase (PAL) links the plant primary and secondary metabolisms, and its product, trans-cinnamic acid, is derived into thousands of diverse phenylpropanoids. Bambusa oldhamii BoPAL4 has broad substrate specificity using L-phenylalanine, L-tyrosine, and L-3,4-dihydroxy phenylalanine (L-DOPA) as substrates to yield trans-cinnamic acid, p-coumaric acid, and caffeic acid, respectively. The optimum reaction pH of BoPAL4 for three substrates was measured at 9.0, 8.5, and 9.0, respectively. The optimum reaction temperatures of BoPAL4 for three substrates were obtained at 50, 60, and 40 °C, respectively. The Km values of BoPAL4 for three substrates were 2084, 98, and 956 μM, respectively. The kcat values of BoPAL4 for three substrates were 1.44, 0.18, and 0.06 σ-1, respectively. The major substrate specificity site mutant, BoPAL4-H123F, showed better affinity toward L-phenylalanine by decreasing its Km value to 640 μM and increasing its kcat value to 1.87 s-1. In comparison to wild-type BoPAL4, the specific activities of BoPAL4-H123F using L-tyrosine and L-DOPA as substrates retained 5.4% and 17.8% residual activities. Therefore, L-phenylalanine, L-tyrosine, and L-DOPA are bona fide substrates for BoPAL4.


1967 ◽  
Vol 105 (1) ◽  
pp. 145-154 ◽  
Author(s):  
G R Whistance ◽  
D R Threlfall ◽  
T W Goodwin

1. p-Hydroxy[U−14C]benzoic acid, except for loss of the carboxyl group, is effectively incorporated into the nucleus of ubiquinone and an unidentified prenylphenol by maize roots, maize shoots, french-bean leaves, french-bean cotyledons and Ochromonas danica. Plastoquinone, α-tocopherol, γ-tocopherol and α-tocopherolquinone are all unlabelled from this substrate. The high radioactivity of the prenylphenol and its behaviour in a pulse-labelling experiment with maize shoots suggested that it may be a ubiquinone precursor. 2. Members of the 2-polyprenylphenol and 6-methoxy-2-polyprenylphenol series, compounds that are known ubiquinone precursors in Rhodospirillum rubrum, could not be detected in maize tissues, but possibly they may occur as their glycosides. 3. [G−14C]Shikimic acid is incorporated into the nuclei of phylloquinone, plastoquinone, α-tocopherolquinone, γ-tocopherol, α-tocopherol and ubiquinone in maize shoots, showing that in plant tissues the nuclei of these compounds arise via the shikimic acid pathway of aromatic biosynthesis. 4. l-[U−14C]Phenylalanine and l-[U−14C]tyrosine are incorporated into plastoquinone, γ-tocopherol, α-tocopherolquinone and ubiquinone. α-Tocopherol, which is absent from shoots incubated with l-[U−14C]tyrosine, is also labelled from l-[U−14C]phenylalanine. Degradation studies showed that there is little 14C radioactivity in the terpenoid portions of the molecules and from this it is concluded that the aromatic portions of these amino acids are giving rise to the quinone and chromanol nuclei. 5. It is proposed that in maize the nucleus of ubiquinone can be formed from either phenylalanine or tyrosine by a pathway involving p-coumaric acid and p-hydroxybenzoic acid. Plastoquinone, tocopherols and tocopherolquinones are formed from tyrosine by some pathway in which the aromatic ring and C-3 of the side chain of this amino acid gives rise to the nucleus and one methyl substituent respectively of these compounds.


1959 ◽  
Vol 37 (4) ◽  
pp. 531-536 ◽  
Author(s):  
D. R. McCalla ◽  
A. C. Neish

C14-Labelled shikimic acid, L-phenylalanine, D-phenylalanine, L-tyrosine, and cinnamic acid were fed separately to leafy cuttings of salvia. After a metabolic period of 24 hours the free and bound phenylalanine, tyrosine, and glutamic acid were isolated from the stems, and their specific activities measured. Shikimic acid was found to be a good precursor of both phenylalanine and tyrosine. There was little interconversion of phenylalanine and tyrosine, and hardly any oxidative breakdown of these compounds to glutamic acid precursors. D-Phenylalanine was metabolized more slowly than L-phenylalanine but it was superior to cinnamic acid as a precursor of bound phenylalanine and tyrosine.


1960 ◽  
Vol 15 (12) ◽  
pp. 768-769 ◽  
Author(s):  
Stewart A. Brown

Tracer experiments with 14C have shown that p-coumaric acid is over 70 times less efficient than cinnamic acid as a precursor of coumarin in Hierochloe odorata, and that tyrosine is over 60 times less efficient than phenylalanine. The results show that in this species the reaction sequence postulated by HAWORTH, in which coumarins are formed from p-coumaric acid, is not significantly involved in the biosynthesis of coumarin itself. It is suggested that, in higher plants, cinnamic acid (or an “activated“ form of it) is a common precursor of all coumarins, and that ortho- or para-hydroxylation of this compound leads subsequently to the formation of coumarin and the 7-hydroxycoumarins, respectively. Different enzyme systems may be required for the formation of the lactone ring of coumarin and the 7-hydroxycoumarins.


1968 ◽  
Vol 106 (2) ◽  
pp. 507-514 ◽  
Author(s):  
Keith Moore ◽  
P. V. Subba Rao ◽  
G. H. N. Towers

Ammonia-lyase activity for l-phenylalanine, m-hydroxyphenylalanine and l-tyrosine was demonstrated in cell-free extracts of Sporobolomyces roseus. Cultures of this organism converted dl-[ring−14C]phenylalanine and l-[U−14C]tyrosine into the corresponding cinnamic acid. Tracer studies showed that these compounds were further metabolized to [14C]protocatechuic acid. Benzoic acid and p-hydroxybenzoic acid were intermediates in this pathway. Washed cells of the organism readily utilized cinnamic acid, p-coumaric acid, caffeic acid, benzoic acid and p-hydroxybenzoic acid. Protocatechuic acid was the terminal aromatic compound formed during the metabolism of these compounds. The cells of S. roseus were able to convert m-coumaric acid into m-hydroxybenzoic acid, but the latter compound, which accumulated in the medium, was not further metabolized. 4-Hydroxycoumarin was identified as the product of o-coumaric acid metabolism by this organism.


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