Inhibition of Ribulose Diphosphate Carboxylase by Cyanide

Claim · model-written summary

Cyanide reversibly inhibited spinach leaf carboxylase by 51% at 10-5 m.

Taxon

SpinachSpinacia oleraceae0

Treatment

10-5 me0

Gene

ribulose 1,5-diphosphate carboxylasee0

Outcome

carboxylation reactione0

Direction

inhibite0

Value

51%e0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim

e0

“Spinach leaf ribulose 1,5-diphosphate carboxylase is reversibly inhibited by cyanide at low concentration; 10-5 m and 10-4 m cyanide inhibit the carboxylation reaction 51% and 91%, respectively”

Claim · model-written summary

Cyanide inhibited carboxylation by 91% at 10-4 m.

Treatment

10-4 m cyanidee0

Outcome

carboxylation reactione0

Direction

inhibite0

Value

91%e0

Not reportedTaxonComparator

Verbatim

e0

“10-5 m and 10-4 m cyanide inhibit the carboxylation reaction 51% and 91%, respectively”

Claim · model-written summary

Cyanide inhibition was uncompetitive with ribulose diphosphate and mixed with Mg2+ and HCO3-.

Outcome

Inhibition by cyanidee0

Value

Ki = 1.6 x 10-5 me0

Not reportedTaxon

Verbatim

e0

“Inhibition by cyanide (Ki = 1.6 x 10-5 m) is uncompetitive (anticompetitive) with respect to ribulose 1,5-diphosphate (ribulose-1,5-di-P) and is of mixed character with respect to Mg2+ and HCO3-”

Claim · model-written summary

Binding studies supported formation of an inactive enzyme–substrate–cyanide complex.

Compound

cyanidee0

Outcome

inactive ternary complexe0

Not reportedTaxon

Verbatim

e0

“The inference that enzyme-ribulose-1,5-di-P complex reacts with cyanide to form an inactive ternary complex is supported by binding studies with the use of the gel filtration technique.”

Claim · model-written summary

Labeled ribulose diphosphate bound tightly to carboxylase only with cyanide.

Outcome

tightly bound to the carboxylasee0

Value

1.04 moles of ribulose-1,5-di-P per mole of enzymee0

Not reportedTaxon

Verbatim

e0

“Ribulose-1,5-di-P uniformly labeled with 14C is tightly bound to the carboxylase (1.04 moles of ribulose-1,5-di-P per mole of enzyme) only in the presence of cyanide”

Claim · model-written summary

Labeled cyanide bound to carboxylase only with ribulose diphosphate.

Outcome

bound to the carboxylasee0

Value

1.06 moles of cyanide per mole of enzymee0

Not reportedTaxon

Verbatim

e0

“14C-cyanide is bound to the carboxylase (1.06 moles of cyanide per mole of enzyme) only in the presence of ribulose-1,5-di-P”

Claim · model-written summary

Mg2+ did not affect either labeled ligand binding measurement.

Outcome

14C-ribulose-1,5-di-P bindinge0

Direction

without effecte0

Not reportedTaxon

Verbatim

e0

“The presence of Mg2+ is without effect on 14C-ribulose-1,5-di-P binding in the presence of cyanide or on 14C-cyanide binding in the presence of ribulose-1,5-di-P under the conditions used”

Claim · model-written summary

The enzyme, substrate and cyanide formed a 1:1:1 ternary complex.

Outcome

ternary complexe0

Value

1:1:1e0

Not reportedTaxon

Verbatim

e0

“A ternary complex of ribulose-1,5-di-P carboxylase, ribulose-1,5-di-P, and cyanide in a mole ratio of 1:1:1 is indicated.”

Claim · model-written summary

Schiff base formation could not be demonstrated.

Outcome

Schiff base formatione0

Direction

unsuccessfule0

Not reportedTaxon

Verbatim

e0

“Attempts to demonstrate Schiff base formation between the carboxylase and ribulose-1,5-di-P under a wide variety of conditions were unsuccessful.”