NAD hydrolysis: Chemical and enzymatic mechanisms

1994 ◽  
Vol 138 (1-2) ◽  
pp. 245-251 ◽  
Author(s):  
Norman J. Oppenheimer
Keyword(s):  
Enzymatic Mechanisms

His -234 is an Essential Residue for Populus tomentosa 4 -coumarate: CoA Ligase Enzymatic Mechanisms

2013 ◽  
Vol 40 (11) ◽  
pp. 1165
Author(s):  
BaiGuang REN ◽  
D-Feng LI ◽  
CaiXia ZHENG ◽  
Ying GAI ◽  
XiangNing JIANG ◽  
...  
Keyword(s):  
Populus Tomentosa ◽  
Coa Ligase ◽  
Enzymatic Mechanisms

scholarly journals Protein lysine crotonylation: past, present, perspective

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Gaoyue Jiang ◽  
Chunxia Li ◽  
Meng Lu ◽  
Kefeng Lu ◽  
Huihui Li
Keyword(s):  
Cross Talk ◽  
Tissue Injury ◽  
Regulatory Mechanisms ◽  
Biological Processes ◽  
Histone Proteins ◽  
Physiological Functions ◽  
Neuropsychiatric Disease ◽  
Enzymatic Mechanisms ◽  
Substrate Proteins ◽  
Tools And Methods

AbstractLysine crotonylation has been discovered in histone and non-histone proteins and found to be involved in diverse diseases and biological processes, such as neuropsychiatric disease, carcinogenesis, spermatogenesis, tissue injury, and inflammation. The unique carbon–carbon π-bond structure indicates that lysine crotonylation may use distinct regulatory mechanisms from the widely studied other types of lysine acylation. In this review, we discussed the regulation of lysine crotonylation by enzymatic and non-enzymatic mechanisms, the recognition of substrate proteins, the physiological functions of lysine crotonylation and its cross-talk with other types of modification. The tools and methods for prediction and detection of lysine crotonylation were also described.

scholarly journals Mechanistic strategies of microbial communities regulating lignocellulose deconstruction in a UK salt marsh

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Daniel R. Leadbeater ◽  
Nicola C. Oates ◽  
Joseph P. Bennett ◽  
Yi Li ◽  
Adam A. Dowle ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Salt Marshes ◽  
Molecular Mechanisms ◽  
Surface Sediments ◽  
Gene Profiling ◽  
Oxidative Enzymes ◽  
Lignocellulose Degradation ◽  
Rrna Gene ◽  
Enzymatic Mechanisms

Abstract Background Salt marshes are major natural repositories of sequestered organic carbon with high burial rates of organic matter, produced by highly productive native flora. Accumulated carbon predominantly exists as lignocellulose which is metabolised by communities of functionally diverse microbes. However, the organisms that orchestrate this process and the enzymatic mechanisms employed that regulate the accumulation, composition and permanence of this carbon stock are not yet known. We applied meta-exo-proteome proteomics and 16S rRNA gene profiling to study lignocellulose decomposition in situ within the surface level sediments of a natural established UK salt marsh. Results Our studies revealed a community dominated by Gammaproteobacteria, Bacteroidetes and Deltaproteobacteria that drive lignocellulose degradation in the salt marsh. We identify 42 families of lignocellulolytic bacteria of which the most active secretors of carbohydrate-active enzymes were observed to be Prolixibacteracea, Flavobacteriaceae, Cellvibrionaceae, Saccharospirillaceae, Alteromonadaceae, Vibrionaceae and Cytophagaceae. These families secreted lignocellulose-active glycoside hydrolase (GH) family enzymes GH3, GH5, GH6, GH9, GH10, GH11, GH13 and GH43 that were associated with degrading Spartina biomass. While fungi were present, we did not detect a lignocellulolytic contribution from fungi which are major contributors to terrestrial lignocellulose deconstruction. Oxidative enzymes such as laccases, peroxidases and lytic polysaccharide monooxygenases that are important for lignocellulose degradation in the terrestrial environment were present but not abundant, while a notable abundance of putative esterases (such as carbohydrate esterase family 1) associated with decoupling lignin from polysaccharides in lignocellulose was observed. Conclusions Here, we identify a diverse cohort of previously undefined bacteria that drive lignocellulose degradation in the surface sediments of the salt marsh environment and describe the enzymatic mechanisms they employ to facilitate this process. Our results increase the understanding of the microbial and molecular mechanisms that underpin carbon sequestration from lignocellulose within salt marsh surface sediments in situ and provide insights into the potential enzymatic mechanisms regulating the enrichment of polyphenolics in salt marsh sediments.

scholarly journals What the Wild Things Do: Mechanisms of Plant Host Manipulation by Bacterial Type III-Secreted Effector Proteins

2021 ◽  
Vol 9 (5) ◽  
pp. 1029
Author(s):  
Karl J. Schreiber ◽  
Ilea J. Chau-Ly ◽  
Jennifer D. Lewis
Keyword(s):  
Pseudomonas Syringae ◽  
Structural Data ◽  
Enzymatic Activities ◽  
Effector Proteins ◽  
Host Recognition ◽  
Plant Host ◽  
Type Iii ◽  
Xanthomonas Species ◽  
Pathogen Fitness ◽  
Enzymatic Mechanisms

Phytopathogenic bacteria possess an arsenal of effector proteins that enable them to subvert host recognition and manipulate the host to promote pathogen fitness. The type III secretion system (T3SS) delivers type III-secreted effector proteins (T3SEs) from bacterial pathogens such as Pseudomonas syringae, Ralstonia solanacearum, and various Xanthomonas species. These T3SEs interact with and modify a range of intracellular host targets to alter their activity and thereby attenuate host immune signaling. Pathogens have evolved T3SEs with diverse biochemical activities, which can be difficult to predict in the absence of structural data. Interestingly, several T3SEs are activated following injection into the host cell. Here, we review T3SEs with documented enzymatic activities, as well as T3SEs that facilitate virulence-promoting processes either indirectly or through non-enzymatic mechanisms. We discuss the mechanisms by which T3SEs are activated in the cell, as well as how T3SEs modify host targets to promote virulence or trigger immunity. These mechanisms may suggest common enzymatic activities and convergent targets that could be manipulated to protect crop plants from infection.

scholarly journals Unveiling the crucial intermediates in androgen production

2015 ◽  
Vol 112 (52) ◽  
pp. 15856-15861 ◽  
Author(s):  
Piotr J. Mak ◽  
Michael C. Gregory ◽  
Ilia G. Denisov ◽  
Stephen G. Sligar ◽  
James R. Kincaid
Keyword(s):  
Bond Cleavage ◽  
Nucleophilic Attack ◽  
Reaction Intermediates ◽  
Structural Determinants ◽  
Initial Product ◽  
Androgen Synthesis ◽  
Ferric Peroxo ◽  
Enzymatic Mechanisms ◽  
Primary Substrate

Ablation of androgen production through surgery is one strategy against prostate cancer, with the current focus placed on pharmaceutical intervention to restrict androgen synthesis selectively, an endeavor that could benefit from the enhanced understanding of enzymatic mechanisms that derives from characterization of key reaction intermediates. The multifunctional cytochrome P450 17A1 (CYP17A1) first catalyzes the typical hydroxylation of its primary substrate, pregnenolone (PREG) and then also orchestrates a remarkable C17–C20 bond cleavage (lyase) reaction, converting the 17-hydroxypregnenolone initial product to dehydroepiandrosterone, a process representing the first committed step in the biosynthesis of androgens. Now, we report the capture and structural characterization of intermediates produced during this lyase step: an initial peroxo-anion intermediate, poised for nucleophilic attack on the C20 position by a substrate-associated H-bond, and the crucial ferric peroxo-hemiacetal intermediate that precedes carbon–carbon (C-C) bond cleavage. These studies provide a rare glimpse at the actual structural determinants of a chemical transformation that carries profound physiological consequences.

Glutaminyl cyclases from animals and plants: a case of functionally convergent protein evolution

2008 ◽  
Vol 389 (8) ◽  
Author(s):  
Stephan Schilling ◽  
Claus Wasternack ◽  
Hans-Ulrich Demuth
Keyword(s):  
Matrix Proteins ◽  
Animal Origin ◽  
Amyloid Peptides ◽  
Evolutionary Origins ◽  
Pathogenesis Related ◽  
Related Proteins ◽  
Mammalian Peptide ◽  
Enzymatic Mechanisms ◽  
Physiological Substrates ◽  
Interaction With Receptors

Abstract Several mammalian peptide hormones and proteins from plant and animal origin contain an N-terminal pyroglutamic acid (pGlu) residue. Frequently, the moiety is important in exerting biological function in either mediating interaction with receptors or stabilizing against N-terminal degradation. Glutaminyl cyclases (QCs) were isolated from different plants and animals catalyzing pGlu formation. The recent resolution of the 3D structures of Carica papaya and human QCs clearly supports different evolutionary origins of the proteins, which is also reflected by different enzymatic mechanisms. The broad substrate specificity is revealed by the heterogeneity of physiological substrates of plant and animal QCs, including cytokines, matrix proteins and pathogenesis-related proteins. Moreover, recent evidence also suggests human QC as a catalyst of pGlu formation at the N-terminus of amyloid peptides, which contribute to Alzheimer's disease. Obviously, owing to its biophysical properties, the function of pGlu in plant and animal proteins is very similar in terms of stabilizing or mediating protein and peptide structure. It is possible that the requirement for catalysis of pGlu formation under physiological conditions may have triggered separate evolution of QCs in plants and animals.

DRUG TESTING IN CHILDREN: FDA REGULATIONS

PEDIATRICS ◽  
1969 ◽  
Vol 43 (3) ◽  
pp. 463-465
Author(s):  
Sumner J. Yaffe ◽  
Mary Ellen Avery ◽  
Arnold P. Gold ◽  
Frederick M. Kenny ◽  
Harris D. Riley ◽  
...  
Keyword(s):  
Body Weight ◽  
Drug Testing ◽  
Sick Child ◽  
Tooth Enamel ◽  
Extended Period ◽  
The Body ◽  
Childhood Disorders ◽  
Genital Development ◽  
Enzymatic Mechanisms ◽  
Prescribing Medication

The testillg of drugs for use ill cilildren is difficult to accomplish, and it is even difficult to write about. Anything that smacks of "experimentation" on a child or even the use of a placebo given to a sick child is an emotionally charged subject. To carry out procedures that cannot be considered as essential to therapy, especially when they are painful or tiresome, seems abhorrent. However, it is recognized that the effects of many drugs on children may vary considerably from the effects on adults even when careful calculation is made to arrive at a dosage proportional to the body weight or estimated body surface area. Pharmacologically, children cannot be regarded as little adults. Intensified, or toxic effects of drugs administered to children, especially infants, may reflect immaturity in enzymatic mechanisms for drug metabolism, as well as other detoxification and excretory functions. In view of these circumstances, there is need for special caution in prescribing medication in the treatment of childhood disorders, particularly when the medication is used for an extended period of time or when a newly marketed drug is employed. Even greater caution is needed with the use of a new drug under investigation, in advance of approval for marketing. Known serious adverse effects of drugs in children include the effects of sex hormones on growth, steroids on genital development, and antibiotics on tooth enamel. According to the regulations of the Food and Drug Administration, a drug which has not been subjected to investigation in children may not be labeled for use in pediatric therapy.

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