scholarly journals Fat metabolism in higher plants. β-hydroxylation of fatty acids by a soluble preparation from maturing avocado mesocarp

1972 ◽  
Vol 130 (4) ◽  
pp. 1013-1018 ◽  
Author(s):  
J. L. Harwood ◽  
A. Sodja ◽  
P. K. Stumpf

1. An avocado supernatant fraction converted fatty acids of medium chain length (C8–C12) into a polar product. 2. The product was identified as the β-hydroxy derivative of the substrate by g.l.c. and t.l.c. analysis. 3. For hydroxylation of the fatty acids, CoA, ATP and molecular oxygen were required. Acyl carrier protein gave some stimulation. The reaction took place with oxygen alone if acyl-CoA was the substrate. 4. Hydroxylation was maximal with decanoic acid but dodecanoic acid and octanoic acid were also very active. Acids of shorter or longer chain lengths were not hydroxylated. 5. NAD+ concentration caused complete inhibition at 0.5mm and may be an important control mechanism for the reaction in vivo. 6. The reaction was inhibited by iodoacetamide and by bipyridyl and carbon monoxide, indicating involvement of thiol and heavy metal groups.

2018 ◽  
Vol 475 (17) ◽  
pp. 2801-2817 ◽  
Author(s):  
Ilona K. Jóźwik ◽  
Martin Litzenburger ◽  
Yogan Khatri ◽  
Alexander Schifrin ◽  
Marco Girhard ◽  
...  

Oxidative biocatalytic reactions performed by cytochrome P450 enzymes (P450s) are of high interest for the chemical and pharmaceutical industries. CYP267B1 is a P450 enzyme from myxobacterium Sorangium cellulosum So ce56 displaying a broad substrate scope. In this work, a search for new substrates was performed, combined with product characterization and a structural analysis of substrate-bound complexes using X-ray crystallography and computational docking. The results demonstrate the ability of CYP267B1 to perform in-chain hydroxylations of medium-chain saturated fatty acids (decanoic acid, dodecanoic acid and tetradecanoic acid) and a regioselective hydroxylation of flavanone. The fatty acids are mono-hydroxylated at different in-chain positions, with decanoic acid displaying the highest regioselectivity towards ω-3 hydroxylation. Flavanone is preferably oxidized to 3-hydroxyflavanone. High-resolution crystal structures of CYP267B1 revealed a very spacious active site pocket, similarly to other P450s capable of converting macrocyclic compounds. The pocket becomes more constricted near to the heme and is closed off from solvent by residues of the F and G helices and the B–C loop. The crystal structure of the tetradecanoic acid-bound complex displays the fatty acid bound near to the heme, but in a nonproductive conformation. Molecular docking allowed modeling of the productive binding modes for the four investigated fatty acids and flavanone, as well as of two substrates identified in a previous study (diclofenac and ibuprofen), explaining the observed product profiles. The obtained structures of CYP267B1 thus serve as a valuable prediction tool for substrate hydroxylations by this highly versatile enzyme and will encourage future selectivity changes by rational protein engineering.


Author(s):  
Rui Gong ◽  
Hong-Mei Xiao ◽  
Yin-Hua Zhang ◽  
Qi Zhao ◽  
Kuan-Jui Su ◽  
...  

Abstract Context Although metabolic profiles appear to play an important role in menopausal bone loss, the functional mechanisms by which metabolites influence bone mineral density (BMD) during menopause are largely unknown. Objective We aimed to systematically identify metabolites associated with BMD variation and their potential functional mechanisms in peri-/post-menopausal women. Design and Methods We performed serum metabolomic profiling and whole-genome sequencing for 517 perimenopausal (16%) and early postmenopausal (84%) women aged 41 to 64 years in this cross-sectional study. Partial least squares (PLS) regression and general linear regression analysis were applied to identify BMD-associated metabolites, and weighted gene co-expression network analysis was performed to construct co-functional metabolite modules. Furthermore, we performed Mendelian randomization analysis to identify causal relationships between BMD-associated metabolites and BMD variation. Finally, we explored the effects of a novel prominent BMD-associated metabolite on bone metabolism through both in vivo/in vitro experiments. Results Twenty metabolites and a co-functional metabolite module (consisting of fatty acids) were significantly associated with BMD variation. We found dodecanoic acid (DA), within the identified module, causally decreased total hip BMD. Subsequently, the in vivo experiments might support that dietary supplementation with DA could promote bone loss, as well as increase the osteoblast and osteoclast numbers in normal/ovariectomized mice. DA treatment differentially promoted osteoblast and osteoclast differentiation, especially for osteoclast differentiation at higher concentrations in vitro (e.g.,10, 100μM). Conclusions This study sheds light on metabolomic profiles associated with postmenopausal osteoporosis risk, highlighting the potential importance of fatty acids, as exemplified by DA, in regulating BMD.


1989 ◽  
Vol 89 (2) ◽  
pp. 707-711 ◽  
Author(s):  
Autar K. Mattoo ◽  
Franklin E. Callahan ◽  
Roshni A. Mehta ◽  
John B. Ohlrogge

Author(s):  
Ourzeddine Widad ◽  
Fadel Hamza ◽  
Mechehoud Youcef ◽  
Chalchat Jean-claude ◽  
Figueredo Gilles ◽  
...  

The essential oil of the fruit of Zizyphus lotus (L.) Desf. belonging to the Rhamnaceae family, was obtained by steam distillation and analyzed by GC-FID and GC-MS. 38 components were identified corresponding to 92% of the total oil. Fatty acids represented the major fraction (78.9%), followed by hydrocarbons (10.8%) while terpenic fraction constituted only 1.1% of the oil (- and β-eudesmol). The fatty acids fraction contained 23 saturated and unsaturated compounds (67.8 and 11%, respectively) from C8 to C18. The major constituents are in decreasing order: ethyl hexadecanoate (12%), decanoic acid (11%), ethyl dodecanoate (9.4%), ethyl hexadec-9-enoate (7.9%), dodecanoic acid (6.5%), ethyl tetradecanoate (6.1%) and tetradecanoic acid (5%). Several studies described the fatty acid composition of different parts of Zizyphus species in the fixed oil. Our study is the first report devoted to the chemical composition of the essential oil of the fruit of this species. The antioxidant property of this oil was evaluated using β-carotene bleaching method.


Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.


1971 ◽  
Vol 26 (03) ◽  
pp. 488-492 ◽  
Author(s):  
Th B. Tschopp ◽  
H.-R Baumgartner ◽  
A Studer

SummaryIn rabbits and cats Congo red administered intravenously causes severe thrombocytopenia and ultrastructural alterations of platelets and leucocytes, similar to those produced by some fatty acids and endotoxin. Transient leucopenia is followed by leucocytosis. In contrast, incubation of Congo red in citrated blood or platelet rich plasma has no effect. Therefore, an indirect mechanism is postulated to explain the in vivo effect of Congo red.


Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 92-OR ◽  
Author(s):  
WEI HUANG ◽  
YONG XU ◽  
YOUHUA XU ◽  
LUPING ZHOU ◽  
CHENLIN GAO

Coronaviruses ◽  
2020 ◽  
Vol 01 ◽  
Author(s):  
Ashraf Talaat Youssef

The pandemic of COVID-19 had started in Wuhan city china in late 2019 with a subsequent worldwide spread. The viral infection can seriousely affect multiple organs mainly lungs, kidneys, heart, liver and brain and may lead to respiratory, renal, cardiac or hepatic failure.Vascular thrombosis of unexplained mechanism that may lead to widespread blood clots in multiple organs and cytokine storms that result of overstimulation of the immune system subsequent of lung damage may lead to sudden decompensation due to hypotension and more damage to liver, kidney, brain or lungs.Until now no drug had proved efficient in getting rid of the problem and controlling the pandemic mainly depends on preventive measures.Many preventive measures can be considered to prevent the worldwide spread of viral transmission. Polyunsaturated long chain fatty acids (PUFAs) and the medium chain saturated fatty acids (MCSFAs) and their corresponding monoglycerides had high antiviral activities against the enveloped viruses which reach to more than 10,000 -fold reduction in the viral titres in vitro and in vivo after testing of its gastric aspirate, and can contribute to the systemic immunity against the enveloped viruses.


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