Publications

• Monoterpene biosynthesis in lemon (Citrus limon): cDNA isolation and functional analysis of four monoterpene synthases.

  Lucker J., El Tamer M.K., Schwab W., Verstappen F.W.A., van der Plas L.H.W., Bouwmeester H.J., Verhoeven H.A.

  Citrus limon possesses a high content and large variety of monoterpenoids, especially in the glands of the fruit flavedo. The genes responsible for the production of these monoterpenes have never been isolated. By applying a random sequencing approach to a cDNA library from mRNA isolated from the ... >> More

  Citrus limon possesses a high content and large variety of monoterpenoids, especially in the glands of the fruit flavedo. The genes responsible for the production of these monoterpenes have never been isolated. By applying a random sequencing approach to a cDNA library from mRNA isolated from the peel of young developing fruit, four monoterpene synthase cDNAs were isolated that appear to be new members of the previously reported tpsb family. Based on sequence homology and phylogenetic analysis, these sequences cluster in two separate groups. All four cDNAs could be functionally expressed in Escherichia coli after removal of their plastid targeting signals. The main products of the enzymes in assays with geranyl diphosphate as substrate were (+)-limonene (two cDNAs) (-)-beta-pinene and gamma-terpinene. All enzymes exhibited a pH optimum around 7; addition of Mn(2+) as bivalent metal ion cofactor resulted in higher activity than Mg(2+), with an optimum concentration of 0.6 mm. K(m) values ranged from 0.7 to 3.1 microm. The four enzymes account for the production of 10 out of the 17 monoterpene skeletons commonly observed in lemon peel oil, corresponding to more than 90% of the main components present. << Less

  Eur. J. Biochem. 269:3160-3171(2002) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Biosynthesis of the monoterpenes limonene and carvone in the fruit of caraway. I. Demonstration Of enzyme activities and their changes with development.

  Bouwmeester H.J., Gershenzon J., Konings M.C., Croteau R.

  The biosynthesis of the monoterpenes limonene and carvone in the fruit of caraway (Carum carvi L.) proceeds from geranyl diphosphate via a three-step pathway. First, geranyl diphosphate is cyclized to (+)-limonene by a monoterpene synthase. Second, this intermediate is stored in the essential oil ... >> More

  The biosynthesis of the monoterpenes limonene and carvone in the fruit of caraway (Carum carvi L.) proceeds from geranyl diphosphate via a three-step pathway. First, geranyl diphosphate is cyclized to (+)-limonene by a monoterpene synthase. Second, this intermediate is stored in the essential oil ducts without further metabolism or is converted by limonene-6-hydroxylase to (+)-trans-carveol. Third, (+)-trans-carveol is oxidized by a dehydrogenase to (+)-carvone. To investigate the regulation of monoterpene formation in caraway, we measured the time course of limonene and carvone accumulation during fruit development and compared it with monoterpene biosynthesis from [U-14C]Suc and the changes in the activities of the three enzymes. The activities of the enzymes explain the profiles of monoterpene accumulation quite well, with limonene-6-hydroxylase playing a pivotal role in controlling the nature of the end product. In the youngest stages, when limonene-6-hydroxylase is undetectable, only limonene was accumulating in appreciable levels. The appearance of limonene-6-hydroxylase correlates closely with the onset of carvone accumulation. At later stages of fruit development, the activities of all three enzymes declined to low levels. Although this correlates closely with a decrease in monoterpene accumulation, the latter may also be the result of competition with other pathways for substrate. << Less

  Plant Physiol 117:901-912(1998) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Molecular cloning, functional expression and characterization of d-limonene synthase from Schizonepeta tenuifolia.

  Maruyama T., Ito M., Kiuchi F., Honda G.

  Limonene is one of the most simple cyclic monoterpenes, and two enantiomers, d- and l-limonene occur due to the chiral carbon at 4-position. Cyclization of GPP into limonene is catalyzed by the limonene synthase, and some l-limonene synthase cDNAs have already been cloned from several species of p ... >> More

  Limonene is one of the most simple cyclic monoterpenes, and two enantiomers, d- and l-limonene occur due to the chiral carbon at 4-position. Cyclization of GPP into limonene is catalyzed by the limonene synthase, and some l-limonene synthase cDNAs have already been cloned from several species of plants, mainly from Labiatae family. However, the d-limonene synthase gene has not yet been obtained, therefore, no information is available on the molecular mechanism of stereochemical regulation in limonene formation. To resolve this, we cloned the d-limonene synthase gene (dLMS) from Schizonepeta tenuifolia (Labiatae) by a reverse genetic approach, and we found that both d- and l-limonene synthase share similar features such as a transit peptide, an arginine rich domain, and a metal cation binding site in their structures. Here, we report on the cloning of dLMS, and the putative stereochemical regulation mechanism is discussed based on the comparison of the deduced amino acid sequence of dLMS with those of known l-limonene synthases. << Less

  Biol Pharm Bull 24:373-377(2001) [PubMed] [EuropePMC]

• Molecular identification of N-acetylaspartylglutamate synthase and beta-citrylglutamate synthase.

  Collard F., Stroobant V., Lamosa P., Kapanda C.N., Lambert D.M., Muccioli G.G., Poupaert J.H., Opperdoes F., Van Schaftingen E.

  The purpose of the present work was to determine the identity of the enzymes that synthesize N-acetylaspartylglutamate (NAAG), the most abundant dipeptide present in vertebrate central nervous system (CNS), and β-citrylglutamate, a structural analogue of NAAG present in testis and immature brain. ... >> More

  The purpose of the present work was to determine the identity of the enzymes that synthesize N-acetylaspartylglutamate (NAAG), the most abundant dipeptide present in vertebrate central nervous system (CNS), and β-citrylglutamate, a structural analogue of NAAG present in testis and immature brain. Previous evidence suggests that NAAG is not synthesized on ribosomes but presumably is synthesized by a ligase. As attempts to detect this ligase in brain extracts failed, we searched the mammalian genomes for putative enzymes that could catalyze this type of reaction. Mammalian genomes were found to encode two putative ligases homologous to Escherichia coli RIMK, which ligates glutamates to the C terminus of ribosomal protein S6. One of them, named RIMKLA, is almost exclusively expressed in the CNS, whereas RIMKLB, which shares 65% sequence identity with RIMKLA, is expressed in CNS and testis. Both proteins were expressed in bacteria or HEK293T cells and purified. RIMKLA catalyzed the ATP-dependent synthesis of N-acetylaspartylglutamate from N-acetylaspartate and l-glutamate. RIMKLB catalyzed this reaction as well as the synthesis of β-citrylglutamate. The nature of the reaction products was confirmed by mass spectrometry and NMR. RIMKLA was shown to produce stoichiometric amounts of NAAG and ADP, in agreement with its belonging to the ATP-grasp family of ligases. The molecular identification of these two enzymes will facilitate progress in the understanding of the function of NAAG and β-citrylglutamate. << Less

  J. Biol. Chem. 285:29826-29833(2010) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Cloning and functional characterization of three terpene synthases from lavender (Lavandula angustifolia).

  Landmann C., Fink B., Festner M., Dregus M., Engel K.H., Schwab W.

  The essential oil of lavender (Lavandula angustifolia) is mainly composed of mono- and sesquiterpenes. Using a homology-based PCR strategy, two monoterpene synthases (LaLIMS and LaLINS) and one sesquiterpene synthase (LaBERS) were cloned from lavender leaves and flowers. LaLIMS catalyzed the forma ... >> More

  The essential oil of lavender (Lavandula angustifolia) is mainly composed of mono- and sesquiterpenes. Using a homology-based PCR strategy, two monoterpene synthases (LaLIMS and LaLINS) and one sesquiterpene synthase (LaBERS) were cloned from lavender leaves and flowers. LaLIMS catalyzed the formation of (R)-(+)-limonene, terpinolene, (1R,5S)-(+)-camphene, (1R,5R)-(+)-alpha-pinene, beta-myrcene and traces of alpha-phellandrene. The proportions of these products changed significantly when Mn(2+) was supplied as the cofactor instead of Mg(2+). The second enzyme LaLINS produced exclusively (R)-(-)-linalool, the main component of lavender essential oil. LaBERS transformed farnesyl diphosphate and represents the first reported trans-alpha-bergamotene synthase. It accepted geranyl diphosphate with higher affinity than farnesyl diphosphate and also produced monoterpenes, albeit at low rates. LaBERS is probably derived from a parental monoterpene synthase by the loss of the plastidial signal peptide and by broadening its substrate acceptance spectrum. The identification and description of the first terpene synthases from L. angustifolia forms the basis for the biotechnological modification of essential oil composition in lavender. << Less

  Arch. Biochem. Biophys. 465:417-429(2007) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.