Relationship of porphobilinogen deaminase activity to chlorophyll content and development of 'Heinz 1350' tomato fruit

Genetic, Physiological and Biochemical Analysis of the Formation of Yellow-green Leaf Color of Burley Tobacco (Nicotiana tabacum)

“…δ-aminolevulinate dehydratase (ALAD) as well as other catalytic enzymes (such as porphobilinogen deaminase and magnesium chelatase) were viewed as key enzyme in chlorophyll biosynthesis (McMahan et al, 1990;Ilag et al, 1994;Cornah et al, 2003;Santos, 2004;Chen et al, 2012), but in our research, the dramatic content difference of the seven synthetic precursors in chlorophyll biosynthesis between Burley21 and Maryland609 was began from PBG ( Fig. 1), so only the activity of ALAD were determine.…”

“…δ-aminolevulinate dehydratase (ALAD), porphobilinogen deaminase (PBGD) and magnesium chelatase (Mgchelatase) were the key enzymes reported in the chlorophyll biosynthesis in higher plants. ALAD catalyzes the production of PBG from ALA, PBGD catalyzes the biosynthesis of hydroxymethylbilane from PBG and Mgchelatase catalyzes the production of Mg-Proto IX (McMahan et al, 1990;Ilag et al, 1994;Cornah et al, 2003;Santos, 2004;Chen et al, 2012). On the other hand, the synthesized chlorophyll was accompanied with degradation spontaneously in plants.…”

Biosynthesis of 1-aminocyclopropane-1-carboxylic acid and ethylene from [delta]-aminolevulinic acid in ripening tomato fruits

“…However, there now is a growing body of evidence that Indicates that ALA may be metabolized via nonporphyrin pathways in a number of organisms, and it was found that ALA could be catabolized to COg and other metabolites (9 23). In previous studies, it was found that both porphobilinogen deaminase, one of the enzymes that converts ALA into porphobilinogen, and chlorophyll content increased to a maximum in 35-day tomato fruits and then decreased to near zero in ripe fruits (20). The objective of this research was to determine whether ALA is converted into ACC and ultimately into CgHy during tomato fruit ripening.…”

“…2). However, it is well known now that porphobilinogen deaminase is still active at this stage of development (20) and that the ALA probably was used for chlorophyll production rather than CgHy production.…”

“…However, with Pénicillium digitatum, there is some disagreement whether or not methionine can be the precursor of CgHy (20,28 Research on CgHy production from fruit tissues has shown that the concentration of free methionine was two to three times higher in unripe fruits than in those fully ripe (4). However, the same researchers also…”