Geranylgeranyl Pyrophosphate Synthetase Research Articles

The Purification of Prenyltransferase and Isopentenyl Pyrophosphate Isomerase of Pumpkin Fruit and Their Some Properties

Prenyltransferase (farnesyl pyrophosphate synthetase) [EC 2.5.1.1] and isopentenylpyrophosphate isomerase [EG 5.3.3.2] were obtained and partially purified from pumpkin fruit. The prenyltransferase preparation catalyzed the condensation of isopentenyl pyrophosphate with dime-thylallyl pyrophosphate as well as with geranyl pyrophosphate to yield trans-trans farnesyl pyrophosphate as a final product, and was free of isopentenyl pyrophosphate isomerase and geranylgeranyl pyrophosphate synthetase activities. Prenyltransferase of pumpkin has properties similar to those of pig liver, showing requirement of Mg++, Km value of 1.3 × 10−6M for geranyl pyrophosphate, and pH optimum at 7.5.

A Long Chain Terpenyl Pyrophosphate Synthetase from Micrococcus lysodeikticus

Abstract A new terpene pyrophosphate synthetase (Enzyme II) distinct from the previously reported geranylgeranyl pyrophosphate synthetase (Enzyme I) has been isolated from extracts of Micrococcus lysodeikticus and partially purified. Enzyme II catalyzes the elongation of terpenoid allyl pyrophosphates by isopentenyl pyrophosphate to long chain products. The order of effectiveness of various allyl pyrophosphates in the elongation reaction is geranyl pyrophosphate g farnesyl pyrophosphate g geranylgeranyl pyrophosphate g dimethylallyl pyrophosphate. Isolation of doubly labeled terpene alcohol from experiments with 14C-isopentenyl pyrophosphate and 3H-farnesyl pyrophosphate and determination of 14C:3H ratios indicates the presence of 7 to 10 isoprene units in the elongation products with a predominance of the C35 and C40 alcohols. The same chain length distribution is estimated from the mass spectra of the acid-hydrolyzed products of Enzyme II. The incorporation of 32P from 32P-isopentenyl pyrophosphate and the acid lability of the 32P-labeled material indicate that the products formed are pyrophosphate derivatives. In contrast to shorter chain terpene pyrophosphates, the products formed by Enzyme II are not cleaved by bacterial alkaline phosphatase. They also have the unusual property of binding very strongly to protein.

The Purification and Properties of Pig Liver Geranyl Pyrophosphate Synthetase

Abstract The purification and properties of geranyl pyrophosphate synthetase are reported. This enzyme is purified simultaneously with the enzyme for the synthesis of farnesyl pyrophosphate. It does not, however, have geranylgeranyl pyrophosphate synthetase activity. This enzyme, obtained as a single band of protein by starch gel electrophoresis, catalyzes the formation of both geranyl and farnesyl pyrophosphates from dimethylallyl pyrophosphate and 4-14C-isopentenyl pyrophosphate. These products have been identified by paper and gas-liquid chromatography. A pH range of 7.0 to 7.8 is optimum for the reaction. A metal ion is required and either Mg++ or Mn++ may be used, but Mn++ inhibits the reaction at concentrations greater than 4 x 10-3 m. Km values for isopentenyl and dimethylallyl pyrophosphates are 1.25 x 10-6 and 2.2 x 10-6 m, respectively. N-Ethylmaleimide and p-chloromercuribenzoate strongly inhibit the synthetase reaction, but iodoacetamide has only a slight inhibitory effect. The s20,w value for the synthetase is 4.7.

Purification of Geranylgeranyl Pyrophosphate Synthetase from Micrococcus lysodeikticus

Purification of Geranylgeranyl Pyrophosphate Synthetase from Micrococcus lysodeikticus