scholarly journals Engineering the nucleotide coenzyme specificity and sulfhydryl redox sensitivity of two stress-responsive aldehyde dehydrogenase isoenzymes of Arabidopsis thaliana

2011 ◽  
Vol 434 (3) ◽  
pp. 459-471 ◽  
Author(s):  
Naim Stiti ◽  
Isaac O. Adewale ◽  
Jan Petersen ◽  
Dorothea Bartels ◽  
Hans-Hubert Kirch

Lipid peroxidation is one of the consequences of environmental stress in plants and leads to the accumulation of highly toxic, reactive aldehydes. One of the processes to detoxify these aldehydes is their oxidation into carboxylic acids catalyzed by NAD(P)+-dependent ALDHs (aldehyde dehydrogenases). We investigated kinetic parameters of two Arabidopsis thaliana family 3 ALDHs, the cytosolic ALDH3H1 and the chloroplastic isoform ALDH3I1. Both enzymes had similar substrate specificity and oxidized saturated aliphatic aldehydes. Catalytic efficiencies improved with the increase of carbon chain length. Both enzymes were also able to oxidize α,β-unsaturated aldehydes, but not aromatic aldehydes. Activity of ALDH3H1 was NAD+-dependent, whereas ALDH3I1 was able to use NAD+ and NADP+. An unusual isoleucine residue within the coenzyme-binding cleft was responsible for the NAD+-dependence of ALDH3H1. Engineering the coenzyme-binding environment of ALDH3I1 elucidated the influence of the surrounding amino acids. Enzyme activities of both ALDHs were redox-sensitive. Inhibition was correlated with oxidation of both catalytic and non-catalytic cysteine residues in addition to homodimer formation. Dimerization and inactivation could be reversed by reducing agents. Mutant analysis showed that cysteine residues mediating homodimerization are located in the N-terminal region. Modelling of the protein structures revealed that the redox-sensitive cysteine residues are located at the surfaces of the subunits.

2021 ◽  
pp. 117119
Author(s):  
Mansoor Ul Hassan Shah ◽  
Ambavaram Vijaya Bhaskar Reddy ◽  
Suzana Yusup ◽  
Masahiro Goto ◽  
Muhammad Moniruzzaman

2012 ◽  
Vol 550-553 ◽  
pp. 3-9
Author(s):  
You Yi Zhu ◽  
Zhang Lei Ning ◽  
Qing Feng Hou ◽  
Ming Lei ◽  
Guo Qing Jian

A serious of alkyl polyoxypropylene sulfonate surfactant was synthesized. The O/W interfacial activity of alkyl polyoxypropylene sulfonate surfactant was investigated. The results showed that the interfacial tension of Indonesia crude oil/formation water could reach ultralow level (10-3mN/m order of the magnitude) under weak alkali (Na2CO3) concentration from 0.4wt% to 1.0wt% with C16PO8S, C16PO10S, C18PO8S and C18PO10S alkyl polyoxypropylene sulfonate respectively. These surfactants showed good interface activity and salt and divalent cation tolerance ability. Combinations of alkyl polyoxypropylene sulfanate homologies with different carbon chain length could significantly improve the interface activity. The IFT of Indonesia oil/formation water could reach ultralow interfacial tension under alkali free conditions. The combination of alkyl polyoxypropylene sulfonate surfactant with petroleum sulfonate could improve the salt tolerance ability of formula.


2021 ◽  
Author(s):  
Liwen Zeng ◽  
Kong-qiu Hu ◽  
Zhi-wei Huang ◽  
Lei Mei ◽  
Xianghe Kong ◽  
...  

Herein, we report a new uranyl-organic polyhedron U4L4 (L=BTPCA) assembled from uranyl and a semirigid tritopic ligand. By adjusting the carbon chain length of the organic templates, two complexes can...


2014 ◽  
Vol 82 ◽  
pp. 172-180 ◽  
Author(s):  
En-Jun Gao ◽  
Hong Fu ◽  
Ming-Chang Zhu ◽  
Chi Ma ◽  
Shi-Kai Liang ◽  
...  

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 467
Author(s):  
Shahla S. Smail ◽  
Mowafaq M. Ghareeb ◽  
Huner K. Omer ◽  
Ali A. Al-Kinani ◽  
Raid G. Alany

Nanoemulsions (NE) are isotropic, dispersions of oil, water, surfactant(s) and cosurfactant(s). A range of components (11 surfactants, nine cosurfactants, and five oils) were investigated as potential excipients for preparation of ketorolac tromethamine (KT) ocular nanoemulsion. Diol cosurfactants were investigated for the effect of their carbon chain length and dielectric constant (DEC), Log P, and HLB on saturation solubility of KT. Hen’s Egg Test—ChorioAllantoic Membrane (HET-CAM) assay was used to evaluate conjunctival irritation of selected excipients. Of the investigated surfactants, Tween 60 achieved the highest KT solubility (9.89 ± 0.17 mg/mL), followed by Cremophor RH 40 (9.00 ± 0.21 mg/mL); amongst cosurfactants of interest ethylene glycol yielded the highest KT solubility (36.84 ± 0.40 mg/mL), followed by propylene glycol (26.23 ± 0.82 mg/mL). The solubility of KT in cosurfactants was affected by four molecular descriptors: carbon chain length, DEC, log P and HLB. KT solubility was directly proportional to DEC and the HLB yet, inversely proportional to carbon chain length and log P. All surfactants, except Labrasol ALF, were non-irritant. The majority of cosurfactants were slightly irritant, butylene glycol was a moderate irritant, pentylene and hexylene glycols were strong irritants. These findings will inform experiments aimed at developing NE formulations for ocular administration of KT.


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.


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