A novel pyrophosphate fructose‐6‐phosphate 1‐phosphotransferase from carrot roots Relation to PFK from the same source

Wong, Joshua; Kang, Taewook; Buchanan, Bob B.

doi:10.1016/0014-5793(88)80521-0

Cited by 19 publications

(24 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 1-doublet form (Q,) is similar in subunit composition to the PFP purified from carrot roots ( 18). While further purification is required for a definitive characterization, it seems possible that the 1-singlet (Qo) form corresponds to the minor form earlier seen with wheat seedlings (21).…”

Section: Purification Of Pfp From Mature Green Tomato Fruitmentioning

confidence: 96%

“…Subunit Molecular Mass Determination SDS-PAGE was performed with 7.5 to 15% (w/v) slab gels as described by Laemmli (12) with specifics previously described (18). Protein was stained with Coomassie blue R-250 or silver stain.…”

Section: Protein Determinationmentioning

confidence: 99%

“…Native molecular mass of the individual enzyme forms was determined by gel filtration on a Superose 12 column (HR 1O/ 30) as previously ( 18). …”

Section: Native Molecular Mass Determinationmentioning

confidence: 99%

“…In another case (wheat seedlings), PFP activity has been reported to be associated with two structurally different enzyme forms (21). Finally, in a recent study (18), our laboratory has identified in carrot roots a form of PFP that differs both kinetically and structurally from other forms of the enzyme studied to date.…”

mentioning

confidence: 98%

“…As a result of this unusual kinetic and structural diversity, we have considered the possibility that the properties of PFP depend on the functional nature of the parent tissue (18). That is, the form of PFP present in one tissue with a given metabolic function may differ significantly from the enzyme in a tissue with another function.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Pyrophosphate Fructose-6-P 1-Phosphotransferase from Tomato Fruit

Wong¹,

Kiss²,

Wu³

et al. 1990

Plant Physiol.

Self Cite

View full text Add to dashboard Cite

Three forms of pyrophosphate fructose-6-phosphate 1-phosphotransferase (PFP) were purified from both green and red tomato (Lycopersicon esculentum) fruit: (a) a classical form (designated 02) containing a-(66 kilodalton) and ,B-(60 kilodalton) subunits; (b) a form (01) containing a ,-doublet subunit; and (c) a form (Q0o) that appeared to contain a ,B-singlet subunit. Several lines of evidence suggested that the different forms occur under physiological conditions. Q2 was purified to apparent electrophoretic homogeneity; Q1 and Q0 were highly purified, but not to homogeneity. The distribution of the PFP forms from red (versus green) tomato was: Q2, 29% (90%); 01, 47% (6%); and Q0, 24% (4%). The major difference distinguishing the red from the green tomato enzymes was the fructose-2,6-bisphosphate (Fru-2,6-P2)-induced change in Km for fructose-6-phosphate (Fru-6-P), the 'green forms' showing markedly enhanced affinity on activation (Km decrease of 7-9-fold) and the 'red forms' showing either little change (Q0o, Q1) or a relatively small (2.5-fold) affinity increase (02). The results extend our earlier findings with carrot root to another tissue and indicate that forms of PFP showing low or no affinity increase for Fru 6-P on activation by Fru-2,6-P2 (here 01 and Qo) are associated with sugar storage, whereas the classical form (02), which shows a pronounced affinity increase, is more important for starch storage. from most plant sources is highly stimulated by Fru-2,6-P2 (1, 2, 5, 6, 8-10, 15-18, 20, 21), the enzyme from leaves of CAM plants responds only sluggishly to this activator (5,8,10). In another case (wheat seedlings), PFP activity has been reported to be associated with two structurally different enzyme forms (21). Finally, in a recent study (18), our laboratory has identified in carrot roots a form of PFP that differs both kinetically and structurally from other forms of the enzyme studied to date.As a result of this unusual kinetic and structural diversity, we have considered the possibility that the properties of PFP depend on the functional nature of the parent tissue (18). That is, the form of PFP present in one tissue with a given metabolic function may differ significantly from the enzyme in a tissue with another function. We have put this idea to a further test using pericarp of tomato fruit-a tissue known to change from a starch-storing to a sugar-storing function during ripening (7,14). The results indicate that, while occurring in analogous enzyme forms, the PFPs from green and red fruit show a pronounced difference on activation by Fru-2,6-P2. The activated green forms are characterized by a marked increase in affinity for Fru 6-P, whereas the red forms show either little or no change in this connection. A preliminary account of this work has been published (19

show abstract

Section: Purification Of Pfp From Mature Green Tomato Fruitmentioning

confidence: 96%

Section: Protein Determinationmentioning

confidence: 99%

“…Native molecular mass of the individual enzyme forms was determined by gel filtration on a Superose 12 column (HR 1O/ 30) as previously ( 18). …”

Section: Native Molecular Mass Determinationmentioning

confidence: 99%

mentioning

confidence: 98%

mentioning

confidence: 99%