Claim · model-written summary
In ivy, tyrosine beta-carbon forms the 8-methyl group of delta-tocopherol.
- Taxon
- ivye0
- Organ / stage
- leavese0
- Outcome
- 8-methyl group of delta-tocopherole0
- Qualifier
- beta-carbon atom of tyrosinee0
Not reportedMaterialGeneCompoundInteractorInteractor roleSecond interactorSecond interactor roleTreatmentComparatorSettingDirectionValue
Verbatim
e0“In ivy leaves it is found that the beta-carbon atom of tyrosine gives rise to the 8-methyl group of delta-tocopherol”
Title
G R Whistance; D R Threlfall Biochemical Journal 1968. doi:10.1042/bj1090577
Other claims from this paper (15)
- Observation In maize, phenylalanine or tyrosine forms plastoquinone, gamma-tocopherol and alpha-tocopherolquinone nuclei and methyl groups.
- Observation In maize ubiquinone uses only the amino-acid aromatic ring for its nucleus.
- Observation A directly derived C(6)-C(1) amino-acid unit contributes to plastoquinone and gamma-tocopherol.
- Observation Cinnamic-acid beta-carbon label was not incorporated into the quinones.
- Observation Beans differed from maize because phenylalanine was used only for ubiquinone biosynthesis.
- Mechanism The authors attribute that bean difference to absent phenylalanine hydroxylase.
- Mechanism Ivy tyrosine beta-carbon may form the nuclear methyl group in other compounds.
- Observation Euglena tyrosine ring opening made radiochemical incorporation results uninterpretable.
- Mechanism Higher-plant ubiquinone nuclei can arise from phenylalanine or tyrosine through p-coumaric and p-hydroxybenzoic acids.
- Mechanism Plastoquinone, tocopherols and alpha-tocopherolquinone are formed from p-hydroxyphenylpyruvate.
- Observation Dilution experiments implicate p-hydroxyphenylpyruvic and homogentisic acids in maize plastoquinone biosynthesis.
- Observation Toluquinol showed no dilution effect and its label was not incorporated.
- Observation 3,4-dihydroxybenzaldehyde and 3,4-dihydroxybenzoic acid were excluded from maize ubiquinone and phylloquinone synthesis.
- Observation Aromatic amino-acid ring opening occurs in maize shoots.
- Mechanism The authors suggest maize amino-acid ring opening may occur via homogentisic acid.