Co-factors in Hevea brasiliensis Latex Serum

Abstract

IT has recently been shown¹ that the incorporation of mevalonic acid into rubber by an enzyme system in Hevea latex in vitro is not dependent on the addition of such co-factors as are known to be necessary for the incorporation of mevalonic acid into squalene. Such co-factors include adenosine triphosphate, cysteine and/or glutathione in the case of cell-free preparation of rat liver², although Amdur, Rilling and Bloch³ found that whereas adenosine triphosphate was necessary with a soluble extract of bakers' yeast, no reducing agent requirement was demonstrated. Popjak and Gore show that under anaerobic conditions the reducing agent is not necessary but it is essential for the formation of squalene aerobically. Tchen⁴ has demonstrated that the purified enzyme ‘mevalonic acid-kinase’ responsible for part of the pathway, namely, the phosphorylation of mevalonic acid, requires the presence of any of the four nucleoside triphosphates (including cytidine triphosphate). He shows also that the enzyme is inhibited by chloromercuribenzoate.