Anti-Cancer Agents from Natural Sources
Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg in Promising Drug Molecules of Natural Origin, 2020
There are 20 essential amino acids that considered important and necessary for a healthy life. The human body can fully synthesize in enough quantities the following four essential amino acids: asparagine, glutamic acid, alanine, and aspartic acid, regardless if consumed in diet. The body cannot synthesize phenylalanine, threonine, valine, tryptophan, methionine, leucine, isoleucine, histidine, and lysine, which means they will need to be consumed through diet. The conditional essential amino acids are those that are synthesized under certain conditions like illness, stress, etc. These amino acids include arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline, and serine (Amino Acids, 2018). These amino acids serve as building blocks for several essential proteins and enzymes. Bacterial enzymes are important biocatalysts used by living organisms to catalyze their chemical reactions. Enzymes are made up of amino acids, which contain an amine (-NH2) and carboxyl (-COOH) group, along with a functional and R group. The human body contains thousands of different enzymes that are specifically tailored for specific reactions. Subsequently, many scientists focused on enzymes to discover a possible cure for cancers. Enzymes can be served as a therapeutic agent against cancer because enzymes are highly specific biocatalysts that may transform various substrates into high yield products (Vellard, 2003). Here, three important enzymes that showed anticancer activity viz. L-asparaginase, L-glutaminase, and L-arginase are highlighted (Table 5.2).
Amino acid disorders and urea cycle disorders
Steve Hannigan in Inherited Metabolic Diseases: A Guide to 100 Conditions, 2018
The urea cycle disorders (UCDs) are a group of genetic disorders that are caused by a deficiency of one of six enzymes in the urea cycle, which is responsible for the removal of ammonia. These six enzymes are: arginaseargininosuccinate lyaseargininosuccinate synthetasecarbamyl phosphate synthetaseN-acetylglutamate synthetaseornithine transcarbamylase.
Macronutrients
Chuong Pham-Huy, Bruno Pham Huy in Food and Lifestyle in Health and Disease, 2022
An important function of enzymes is in the digestion of foods. The metabolism of protein foods involves a decomposition into single amino acids by different digestive enzymes (amylase, protease, pepsin, trypsin, and chymotrypsin) from the stomach to the small intestine. Before the absorption in the small intestine, most proteins must be reduced to single amino acid or peptides by specific protein enzymes. Most peptides longer than four amino acids are not absorbed and must be broken into single amino acids. Enzyme production and activity can be decreased with age and illness. Enzymes are present in all foods. However, heat used in cooking, drying, or processing can destroy them. Therefore, fresh foods like fruits and some vegetables are rich in enzymes and help digestion. Some people like to eat raw meat such as raw beefsteak and raw fresh fish; this habit might be helpful for digestion. Enzymes extracted from fruits like papaya, pineapple, kiwifruit, and fig are used as medicines, food-processing agents and dietary supplements. Fruits like papaya, kiwifruit, pineapple and figs are rich in proteases such as papain, actinidin, bromelain, and ficin, respectively, which aid the breakdown of proteins.
The oceans are changing: impact of ocean warming and acidification on biofouling communities
Published in Biofouling, 2019
Sergey Dobretsov, Ricardo Coutinho, Daniel Rittschof, Maria Salta, Federica Ragazzola, Claire Hellio
Enzymes are biological catalysts that accelerate the rate of specific biochemical reactions. Most enzymes are proteins and their structure is important for their activity. Increased temperature and changes in pH can lead to partial inhibition and in extreme cases to inactivation of enzymes (Iyer and Ananthanarayan 2008). However, in other cases such as the activity of trypsin-like enzymes (Rittschof, 2017) increased temperature and lowered pH are near the optimum for the enzymes and increase rates of reactions. When marine organisms are subjected to environmental change (Hochachka and Somero 2002), the three main mechanisms used to maintain physiological homeostasis are: (1) quantitative (changing the concentration of enzymes and/or reactants), (2) qualitative (using a protein variant) and (3) modulation (modifying the protein environment to reduce the impact of environmental change) (Clarke 2003).
Recent advances in the development of polyethylenimine-based gene vectors for safe and efficient gene delivery
Published in Expert Opinion on Drug Delivery, 2019
Cuiping Jiang, Jiatong Chen, Zhuoting Li, Zitong Wang, Wenli Zhang, Jianping Liu
As the substances that are inherently present in the human body, biological molecules draw growing interests as promising triggering motifs in the design of smart PEI-based gene vectors. Among different classes of biological components, ATP, enzyme, glucose, and antigen are the most attractive endogenous stimuli that enable biomolecule-responsive release. As we all know, enzymes are potent catalysts during almost all biological processes, and enzyme catalysis is highly selective towards specific substrates under mild conditions. Using tumor as an example again, several enzymes (i.e. proteases, lipase, hyaluronidase (HAase), etc.) have great potential to be specific stimuli in a controlled gene delivery system [117]. For instance, Yin et al. [118] reported an HA-conjugated PEI polymer for the active tumor targeting via interaction of HA with CD44 receptor. Once the nanocarrier reached the tumor extracellular matrix, the surface layer of HA would be deshielded under the catalysis of HAase, leading to the enhanced cellular uptake owing to the exposure of positive charges.
Antiplatelet properties of snake venoms: a mini review
Published in Toxin Reviews, 2020
Rogayyeh Rashidi, Mahmoud Gorji Valokola, Seyedeh Zohreh Kamrani Rad, Leila Etemad, Ali Roohbakhsh
Snake venom serine proteases (SVSPs, 20–100 kDa) have been extracted mainly from venoms of Viperidae, Elapidae, Viperidae, Hydrophidae, and Colubridae families (Vaiyapuri et al. 2011). They have a conserved domain consisting of three amino acids including histidine, serine, and aspartic acid. All of these amino acids participate in the catalytic activity of the enzymes (Fatima and Fatah 2014). Most of the serine proteases target platelets, coagulation process, and the fibrinolytic system. A few venom serine proteases specifically activate coagulation factor V, protein C, plasminogen, and platelets (Serrano and Maroun 2005). These enzymes have been named as snake venom thrombin-like enzymes (SVTLEs) (Castro et al. 2004). The main recognized target for SVSPs is the coagulation cascade. They are potent platelet aggregating biomolecules and act as exogenous factors of the plasma (Kini 2005, Serrano 2013, Fatima and Fatah 2014). FXa, a trypsin-like serine protease plays a key role in both internal and external coagulation pathways. Therefore, it has the main role in the production of thrombin, which leads to clot formation and wound closure (Jiang et al. 2014, Chen et al. 2015). Some serine proteases present thrombin-like properties and induce abnormal fibrin clots (Figure 2). However, there are snake venoms such as batroxase with both fibrinolytic and fibrinogenolytic activity (Cintra et al. 2012). Some others, such as AHP-Ka, have kininogenase (kallikrein-like,) properties that increase bradykinin and exhibit hypotensive effects (Zhang et al. 2012).
Related Knowledge Centers
- Catalysis
- Chemical Reaction
- Enzyme Catalysis
- Metabolic Pathway
- Molecule
- Protein
- Metabolism
- Substrate
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- Cell