Protonation-Triggered Carbon-Chain Elongation in Geranyl Pyrophosphate Synthase (GPPS)

ACS Catalysis ◽  
2015 ◽  
Vol 5 (7) ◽  
pp. 4466-4478 ◽  
Author(s):  
Jingwei Zhou ◽  
Xiaoming Wang ◽  
Ming Kuang ◽  
Laiyou Wang ◽  
Hai-Bin Luo ◽  
...  

2021 ◽  
Vol 329 ◽  
pp. 124893
Author(s):  
Shanbiao Xie ◽  
Jingwei Ma ◽  
Lu Li ◽  
Qiulai He ◽  
Peng Xu ◽  
...  


Fermentation ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 92 ◽  
Author(s):  
Drishti Dinesh Bhagchandanii ◽  
Rishi Pramod Babu ◽  
Jayesh M. Sonawane ◽  
Namita Khanna ◽  
Soumya Pandit ◽  
...  

Electro-fermentation (EF) is an upcoming technology that can control the metabolism of exoelectrogenic bacteria (i.e., bacteria that transfer electrons using an extracellular mechanism). The fermenter consists of electrodes that act as sink and source for the production and movement of electrons and protons, thus generating electricity and producing valuable products. The conventional process of fermentation has several drawbacks that restrict their application and economic viability. Additionally, metabolic reactions taking place in traditional fermenters are often redox imbalanced. Almost all metabolic pathways and microbial strains have been studied, and EF can electrochemically control this. The process of EF can be used to optimize metabolic processes taking place in the fermenter by controlling the redox and pH imbalances and by stimulating carbon chain elongation or breakdown to improve the overall biomass yield and support the production of a specific product. This review briefly discusses microbe-electrode interactions, electro-fermenter designs, mixed-culture EF, and pure culture EF in industrial applications, electro methanogenesis, and the various products that could be hence generated using this process.



ChemInform ◽  
2010 ◽  
Vol 32 (46) ◽  
pp. no-no
Author(s):  
Morten Joergensen ◽  
Erik H. Iversen ◽  
Robert Madsen


2014 ◽  
Vol 10 ◽  
pp. 2230-2234 ◽  
Author(s):  
Christopher Albler ◽  
Ralph Hollaus ◽  
Hanspeter Kählig ◽  
Walther Schmid

Higher aminosugars are interesting targets in carbohydrate synthesis since these compounds play important roles in biological systems. However, their availability from natural sources is limited. Thus, in order to investigate their biological function, the development of facile and adaptable routes to this class of compounds is of fundamental importance. Our synthetic route towards these target molecules makes use of readily accessible pentoses and hexoses, which are subjected to indium-mediated two-carbon chain elongation. Subsequent ozonolysis and treatment with base yields α,β-unsaturated aldehydes, which are stereoselectively epoxidized using Jørgenson’s protocol. After Wittig chain elongation the obtained allylic epoxides were regio- and stereoselectively opened with trimethylsilyl azide under palladium catalysis. Finally, a suitable deprotection protocol, starting with acidic acetate cleavage and ozonolysis was established. Peracetylation of the products simplifies purification and subsequent azide reduction followed by final deacetylation using methanolic sodium methoxide furnishes the title compounds.



ChemInform ◽  
2010 ◽  
Vol 33 (32) ◽  
pp. no-no
Author(s):  
Ursula Mullenmeister ◽  
Wolf-Dieter Fessner


2013 ◽  
Vol 69 (1) ◽  
pp. 62-68 ◽  
Author(s):  
M. T. Agler ◽  
C. M. Spirito ◽  
J. G. Usack ◽  
J. J. Werner ◽  
L. T. Angenent

High productivity and specificity in anaerobic digesters arise because complex microbiomes organize into a metabolic cascade to maximize energy recovery and to utilize the advantage that the gaseous end product methane freely bubbles out of the system. These lessons were applied to ascertain whether a reactor microbiome could be shaped to produce a different end product. The liquid product n-caproic acid was chosen, which is a 6-carbon-chain carboxylic acid that is valuable and that has a relatively low maximum solubility concentration for product recovery. Acetoclastic methanogenesis was inhibited by pH control and a route was provided for n-caproic acid extraction by implementing selective, in-line recovery. Next, ethanol was supplemented to promote chain elongation, which is a pathway in which short-chain carboxylic acids are elongated sequentially into medium-chain carboxylic acids with two-carbon units derived from ethanol. The reactor microbiome developed accordingly with the terminal process catalyzed by chain-elongating bacteria. As a result, n-caproic acid production rates increased to levels comparable to anaerobic digestion systems for solid waste treatment.



2013 ◽  
Vol 9 ◽  
pp. 2641-2659 ◽  
Author(s):  
Mikko Passiniemi ◽  
Ari MP Koskinen

Since its introduction to the synthetic community in 1984, Garner’s aldehyde has gained substantial attention as a chiral intermediate for the synthesis of numerous amino alcohol derivatives. This review presents some of the most successful carbon chain elongation reactions, namely carbonyl alkylations and olefinations. The literature is reviewed with particular attention on understanding how to avoid the deleterious epimerization of the existing stereocenter in Garner’s aldehyde.



1992 ◽  
Vol 287 (1) ◽  
pp. 91-100 ◽  
Author(s):  
L Cook ◽  
M N Nagi ◽  
S K Suneja ◽  
A R Hand ◽  
D L Cinti

The present study provides strong evidence that the previously isolated hepatic microsomal beta-hydroxyacyl-CoA dehydrase (EC 4.2.1.17), believed to be a component of the fatty acid chain-elongation system, is derived, not from the endoplasmic reticulum, but rather from the peroxisomes. The isolated dehydrase was purified over 3000-fold and showed optimal enzymic activity toward beta-hydroxyacyl-CoAs or trans-2-enoyl-CoAs with carbon chain lengths of 8-10. The purified preparation (VDH) displayed a pH optimum at 7.5 with beta-hydroxydecanoyl-CoA, and at 6.0 with beta-hydroxystearoyl-CoA. Competitive-inhibition studies suggested that VDH contained dehydrase isoforms, and SDS/PAGE showed three major bands at 47, 71 and 78 kDa, all of which reacted to antibody raised to the purified preparation. Immunocytochemical studies with anti-rabbit IgG to VDH unequivocally demonstrated gold particles randomly distributed throughout the peroxisomal matrix of liver sections from both untreated and di-(2-ethylhexyl) phthalate-treated rats. No labelling was associated with endoplasmic reticulum or with the microsomal fraction. Substrate-specificity studies and the use of antibodies to VDH and to the peroxisomal trifunctional protein indicated that VDH and the latter are separate enzymes. On the other hand, the VDH possesses biochemical characteristics similar to those of the D-beta-hydroxyacyl-CoA dehydrase recently isolated from rat liver peroxisomes [Li, Smeland & Schulz (1990) J. Biol. Chem. 265, 13629-13634; Hiltunen, Palosaari & Kunau (1989) J. Biol. Chem. 264, 13536-13540]. Neither enzyme utilizes crotonoyl-CoA or cis-2-enoyl-CoA as substrates, but both enzymes convert trans-2-enoyl substrates into the D-isomer only. In addition, the VDH also contained beta-oxoacyl-CoA reductase (beta-hydroxyacyl-CoA dehydrogenase) activity, which co-purified with the dehydrase.



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