scholarly journals Structure and Mechanism of an Arabidopsis Medium/Long-Chain-Length Prenyl Pyrophosphate Synthase

2011 ◽  
Vol 155 (3) ◽  
pp. 1079-1090 ◽  
Author(s):  
Fu-Lien Hsieh ◽  
Tao-Hsin Chang ◽  
Tzu-Ping Ko ◽  
Andrew H.-J. Wang
1996 ◽  
Vol 1996 ◽  
pp. 98-98
Author(s):  
B M L McLean ◽  
R W Mayes ◽  
F D DeB Hovell

Alkanes occur naturally in all plants, although forage crops tend to have higher alkane contents than cereals. N-alkanes have odd-numbered carbon chains. They are ideal for use as markers in feed trials, because, they are inert, indigestible and naturally occurring, and can be recovered in animal faeces. Synthetic alkanes (even-numbered carbon chains) are available commercially and can also used as external markers. Dove and Mayes (1991) cite evidence indicating that faecal recovery of alkanes in ruminants increases with increasing carbon-chain length. Thus the alkane “pairs” (e.g. C35 & C36, and C32 & C33) are used in calculating intake and digestibility because they are long chain and adjacent to each other. However, recent work by Cuddeford and Mayes (unpublished) has found that in horses the faecal recovery rates are similar regardless of chain lengths.


2012 ◽  
Vol 108 (4) ◽  
pp. 755-758 ◽  
Author(s):  
Charlotte J. Harden ◽  
Adam N. Jones ◽  
Tannia Maya-Jimenez ◽  
Margo E. Barker ◽  
Natalie J. Hepburn ◽  
...  

Long-chain fatty acids have been shown to suppress appetite and reduce energy intake (EI) by stimulating the release of gastrointestinal hormones such as cholecystokinin (CCK). The effect of NEFA acyl chain length on these parameters is not comprehensively understood. Anin vitroscreen tested the capacity of individual NEFA (C12 to C22) to trigger CCK release. There was a gradient in CCK release with increasing chain length. DHA (C22) stimulated significantly (P < 0·01) more CCK release than all other NEFA tested. Subsequently, we conducted a randomised, controlled, crossover intervention study using healthy males (n18). The effects of no treatment (NT) and oral doses of emulsified DHA-rich (DHA) and oleic acid (OA)-rich oils were compared using 24 h EI as the primary endpoint. Participants reported significantly (P = 0·039) lower total daily EI (29 % reduction) with DHA compared to NT. There were no differences between DHA compared to OA and OA compared to NT. There was no between-treatment difference in the time to, or EI of, the first post-intervention eating occasion. It is concluded that NEFA stimulate CCK release in a chain length-dependent manner up to C22. These effects may be extended to thein vivosetting, as a DHA-based emulsion significantly reduced short-term EI.


2020 ◽  
Vol 15 (5) ◽  
pp. 1934578X2092607
Author(s):  
Biljana Nikolić ◽  
Marina Todosijević ◽  
Iris Đorđević ◽  
Jovana Stanković ◽  
Zorica S. Mitić ◽  
...  

In leaf cuticular wax of Pinus pinaster, content of nonacosan-10-ol is high (77.1% on average). n-Alkanes ranged from C18 to C35 with the most dominant C29 (24.8%). The carbon preference index (CPItotal) ranged from 3.1 to 5.6 (4.0 on average), while the average chain length (ACLtotal) ranged from 14.0 to 17.0 (14.8 on average). Long-chain n-alkanes ( n-C25-35) strongly dominated (80.1%) over middle-chain ( n-C21-24 = 18.9%) and short-chain ( n -C18-20 = 0.9%) n-alkanes.


Author(s):  
A P Day ◽  
M D Feher ◽  
R Chopra ◽  
P D Mayne

Intestinal alkaline phosphatase (IALP) activity rises following the ingestion of a fat-containing meal. Previous studies on intestinal fluid and lymph have shown that the magnitude of this response is dependent upon fatty acid chain length. To examine this relation in the serum of healthy humans, 10 subjects consumed two standardized fat meals. One meal contained predominantly long chain fatty acid triglycerides, the other contained predominantly medium chain fatty acid triglycerides. Serum IALP activity was measured in serial blood samples using a sensitive immunological assay. IALP activity was ABO blood group and secretor status dependent. The post-prandial rise in serum IALP activity was significantly greater following the long chain fatty acid meal than following the medium chain fatty acid meal. Previous observations of the fatty acid chain length dependency of the IALP response to fat ingestion, therefore, also apply in the serum of healthy humans under normal physiological conditions. Standardized fat meals provide the basis of a useful method for the investigation of the role of IALP in fat absorption.


Biologia ◽  
2008 ◽  
Vol 63 (6) ◽  
Author(s):  
Wataru Saburi ◽  
Hironori Hondoh ◽  
Young-Min Kim ◽  
Haruhide Mori ◽  
Masayuki Okuyama ◽  
...  

AbstractDextran glucosidase from Streptococcus mutans (SMDG), an exo-type glucosidase of glycoside hydrolase (GH) family 13, specifically hydrolyzes an α-1,6-glucosidic linkage at the non-reducing ends of isomaltooligosaccharides and dextran. SMDG shows the highest sequence similarity to oligo-1,6-glucosidases (O16Gs) among GH family 13 enzymes, but these enzymes are obviously different in terms of substrate chain length specificity. SMDG efficiently hydrolyzes both short-and long-chain substrates, while O16G acts on only short-chain substrates. We focused on this difference in substrate specificity between SMDG and O16G, and elucidated the structure-function relationship of substrate chain length specificity in SMDG. Crystal structure analysis revealed that SMDG consists of three domains, A, B, and C, which are commonly found in other GH family 13 enzymes. The structural comparison between SMDG and O16G from Bacillus cereus indicated that Trp238, spanning subsites +1 and +2, and short β → α loop 4, are characteristic of SMDG, and these structural elements are predicted to be important for high activity toward long-chain substrates. The substrate size preference of SMDG was kinetically analyzed using two mutants: (i) Trp238 was replaced by a smaller amino acid, alanine, asparagine or proline; and (ii) short β → α loop 4 was exchanged with the corresponding loop of O16G. Mutant enzymes showed lower preference for long-chain substrates than wild-type enzyme, indicating that these structural elements are essential for the high activity toward long-chain substrates, as implied by structural analysis.


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