Abstract
Pyrophosphate: fructose 6-phosphate phos-photransferase (PFP) has been partially purifiedfrom ripening banana fruit. The kinetic proper-ties of the activation of banana PFP by Fru-2,6-P_2have been studied. Fru-2, 6-P_2 activated enzymeactivity of fructose 6-phosphate phosphorylationby decreasing K_m(F6P) and increasing V_(max)with a K_a of 30 nmol/L. The activatipn of PFPby Fru-2, 6-P_2 was affected by substrate concentra-tion (F6P). The K_a of Fru-2, 6-P_2 was decreasedfrom 34 nmol/L to 18 nmol/L with the increase ofFru-6-P concentration from 0.5 mmol/L to 14mmol/L at 25℃. The influence of temperatureat 10℃ to 40℃ on Fru-2, 6-P_2 activation ofPFP showed that the kinetic properties of thesaturation curve of Fru-2, 6-P_2 changed. En-zyme cooperativity became positive with the in-creased temperature (Hill number changed from0.8 to 1.3 at 10℃ to 40℃ ) and the K_a fro Fru-2,6-P_2 was decreased from 46 nmol/L to 22 nmol/L.The dependence of enzyme Fru-2, 6-P_2activation on Fru-6-P concentrations and tempera-ture indicated that the binding of enzyme withactivator Fru-2, 6-P_2 could be well modulated andwas significant for regulating PFP enzyme activityduring banana fruit ripening. Changes in the activities of PFP and ATP-dependent phosphofructokinase (PFK) wereobserved during banana fruit ripening. PFPactivity increased rapidly after 3～5 days of retar-dation and the activity of PFP was about 10--foldhigher than the activity of PFK at the 6th day(dimacteric peak). Treatment of banana fruitwith ethylene reduced the length of the preclimac-teric period of respiration which was associatedwith the activity of PFP and the progress of fruitripening. The function and regulation of PFP in fruitripening are discussed.
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Claims 10
Claim · model-written summary
Fru-2,6-P2 activated banana PFP by decreasing Km(F6P).
Verbatim
t0“Banana Fruit”
e0“Fru-2, 6-P_2 activated enzymeactivity of fructose 6-phosphate phosphorylationby decreasing K_m(F6P) and increasing V_(max)with a K_a of 30 nmol/L.”
e1“PFP enzyme activityduring banana fruit ripening”
Claim · model-written summary
Fru-2,6-P2 activated banana PFP by increasing Vmax, with Ka 30 nmol/L.
Verbatim
t0“Banana Fruit”
e0“Fru-2, 6-P_2 activated enzymeactivity of fructose 6-phosphate phosphorylationby decreasing K_m(F6P) and increasing V_(max)with a K_a of 30 nmol/L.”
e1“PFP enzyme activityduring banana fruit ripening”
Claim · model-written summary
Increasing Fru-6-P concentration decreased the Ka of Fru-2,6-P2 from 34 to 18 nmol/L.
Verbatim
t0“Banana Fruit”
e0“The K_a of Fru-2, 6-P_2 was decreasedfrom 34 nmol/L to 18 nmol/L with the increase ofFru-6-P concentration from 0.5 mmol/L to 14mmol/L at 25℃.”
Claim · model-written summary
Increasing temperature made PFP cooperativity positive, with Hill number changing from 0.8 to 1.3.
Verbatim
t0“Banana Fruit”
e0“En-zyme cooperativity became positive with the in-creased temperature (Hill number changed from0.8 to 1.3 at 10℃ to 40℃ ) and the K_a fro Fru-2,6-P_2 was decreased from 46 nmol/L to 22 nmol/L.”
Claim · model-written summary
Increasing temperature decreased Fru-2,6-P2 Ka from 46 to 22 nmol/L.
Verbatim
t0“Banana Fruit”
e0“En-zyme cooperativity became positive with the in-creased temperature (Hill number changed from0.8 to 1.3 at 10℃ to 40℃ ) and the K_a fro Fru-2,6-P_2 was decreased from 46 nmol/L to 22 nmol/L.”
Claim · model-written summary
The authors interpret Fru-2,6-P2 binding as regulating PFP activity during ripening.
Verbatim
t0“Banana Fruit”
e0“The dependence of enzyme Fru-2, 6-P_2activation on Fru-6-P concentrations and tempera-ture indicated that the binding of enzyme withactivator Fru-2, 6-P_2 could be well modulated andwas significant for regulating PFP enzyme activityduring banana fruit ripening.”
Claim · model-written summary
PFP activity increased rapidly after 3 to 5 days of retardation.
Verbatim
t0“Banana Fruit”
e0“PFPactivity increased rapidly after 3～5 days of retar-dation and the activity of PFP was about 10--foldhigher than the activity of PFK at the 6th day(dimacteric peak).”
Claim · model-written summary
PFP activity was about tenfold higher than PFK activity on day six.
Verbatim
t0“Banana Fruit”
e0“PFPactivity increased rapidly after 3～5 days of retar-dation and the activity of PFP was about 10--foldhigher than the activity of PFK at the 6th day(dimacteric peak).”
Claim · model-written summary
Ethylene reduced the preclimacteric respiration period.
- Taxon
- Banana Fruitt0
- Treatment
- ethylenee0
- Outcome
- length of the preclimac-teric period of respiratione0
- Direction
- reducede0
Not reportedComparator
Verbatim
t0“Banana Fruit”
e0“Treatment of banana fruitwith ethylene reduced the length of the preclimac-teric period of respiration which was associatedwith the activity of PFP and the progress of fruitripening.”
Claim · model-written summary
The preclimacteric period was associated with PFP activity and fruit ripening.
Not reportedDirection
Verbatim
t0“Banana Fruit”
e0“Treatment of banana fruitwith ethylene reduced the length of the preclimac-teric period of respiration which was associatedwith the activity of PFP and the progress of fruitripening.”
The same questions in other papers
ethene · physiology: respiration · MusaPositive and negative results
2 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.