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Bio-based Material Protein and Its Novel Applications
Published in Shakeel Ahmed, Saiqa Ikram, Suvardhan Kanchi, Krishna Bisetty, Biocomposites, 2018
Tanvir Arfin, Pooja R. Mogarkar
These are proteins carrying metal ions such as Fe, Mg, Cu, and Co or a colored compound as the prosthetic group due to which the protein appears colored. Examples include chlorophyll in plant, hemoglobin in blood, myoglobin, cytochromes (red colored), flavoproteins (yellow colored), and hemocyanin (blue colored). Metalloproteins are complexes of proteins and heavy metals. In most metalloproteins, the metal is loosely bound and can be easily removed. However, in some proteins such as hemoglobin and myoglobin, the metal iron is firmly bound to the prosthetic group. Liver and spleen contain the metalloproteins ferritin and hemosiderin with about 20% iron content. These are storage forms of iron in animals, which release iron from the proteins when required. Conalbumin from egg can form complex with iron, and it also combines with copper and zinc.
Alpha-Amylase, Protease, Lipase, and High-Fructose Corn Syrup Production
Published in Debabrata Das, Soumya Pandit, Industrial Biotechnology, 2021
These types of enzyme have secreted or transmembrane enzyme families which process and degrade various proteins. Metalloproteinases are characterized as secreted or membrane-anchored metalloproteinases. These classes of enzyme consist of Zn2+ or Ca2+ at their active site. Metalloprotein metal ions generally interact with a water molecule and enhance reactivity (Brouta et al., 2001).
Prospects for Exploiting Microbes and Plants for Bioremediation of Heavy Metals
Published in Maulin P. Shah, Removal of Refractory Pollutants from Wastewater Treatment Plants, 2021
Hiren K. Patel, Rishee K. Kalaria, Divyesh K. Vasava
Toxic metal species will bind to proteins and thereby have an effect on the biological functions of the target molecule. For example, biomass and soil nutrient production of the microorganisms are adversely riddled with the high metal levels of copper and zinc. Additionally, cyanogenic metal might move powerfully within thiols and disulphides and then cause disruption of the biological activity of bound proteins that contain sensitive S teams. These reactions frequently release ROS that are natural by-products of the traditional metabolism. The destruction of sensitive thiol teams thanks to metal exposure might eventually impair the macromolecule folding or binding of apoenzymes by cofactors, and therefore the traditional biological activity of the proteins is discontinuous. Moreover, bound metals in transition will participate in chemical reactions, referred to as Fenton-type reactions, that turn out ROS. Together, these reactions will put the cell under aerophilous stress and thereby the ROS levels will be considerably exaggerated, which can end in polymer injury, the destruction of lipids and proteins through a variety of organic chemistry routes. Cyanogenic metal species may additionally enter cells through various transporters, or penetrate the cellular membrane and then bind to a lipotropic carrier. The transporter-mediated uptake of cyanogenic metals interferes with the traditional transport of essential substrates and therefore leads to the competitive inhibition of the transport method. Moreover, this transport method acquires energy from the nucleon driving force or nucleotide pool. Some metal oxyanions are reduced by the oxidoreductases that are able to draw electrons from the microorganism transport chain through the chemical compound pool (Su et al., 2011). Explicit cyanogenic metals will cause starvation of the microorganism cells indirectly by siphoning electrons from the metastasis chain. The ROS are created throughout traditional metabolic processes and lead to polymer injury and the destruction of proteins and lipids, but this production is continued throughout the metal pollution process and could result in further cellular damage. Macomber & Hausinger (2011) have advised four mechanisms of metallic element toxicity that involves (a) the replacement of an essential metal by metalloprotein: a macromolecule with a metal particle co-factor, (b) a metallic element that binds to chemical action sites of non-metalloenzymes, (c) a metallic element that binds outside the chemical action site of the associate protein to inhibit its operatation, and (d) a metallic element that indirectly causes aerophilous stress. In another example, the loss of cell viability when chromium (III) exposure wasn't as a result of the membrane injury or catalyst inhibition was, however, in all probability as a result of a chromium (III) cyanogenic result on the cellular morphology of the microorganism. When chromium (VI) was exposed to the cell, the cyanogenic result of chromium (III) seemed to be related to the interaction between living things, which ultimately resulted in misshapen cell morphology.
A review on bio-functional models of catechol oxidase probed by less explored first row transition metals
Published in Journal of Coordination Chemistry, 2022
Rashmi Rekha Tripathy, Shuvendu Singha, Sohini Sarkar
Iron-containing metalloproteins are numerous in nature. They are known for versatile biophysical applications in living organisms such as humans, plants, animals, arthropods, mollusks and bacteria. Many of them play a significant role in oxygen binding and transport (hemoglobin, hemoerythrin, chlocruorin). Moreover, as electron carriers (rubredoxin) and as electron transfer vectors (cyctchrome) they have other contributions. Iron-containing metalloenzymes like hydrogenase and catalase can participate in many important redox processes occurring in cells, while the first one helps in reversible hydrogen uptake in different microbes, the second one catalyzes dismutation of hydrogen peroxide to water and oxygen. It helps to protect cells from oxidative damage by reactive oxygen species like peroxides [75]. Catechol dioxygenase is another example of an iron-based enzyme which can catalyze oxidation of ortho diphenols (catechols) by oxidative cleavage of a C—C bond present in the phenolic substrates followed by oxygen insertion. Its mechanism is quite different than that of catechol oxidase although both involve oxidation of catechols or catecholic substrates to the corresponding quinones.
Heavy metal remediation and resistance mechanism of Aeromonas, Bacillus, and Pseudomonas: A review
Published in Critical Reviews in Environmental Science and Technology, 2022
Ali Fakhar, Bushra Gul, Ali Raza Gurmani, Shah Masaud Khan, Shafaqat Ali, Tariq Sultan, Hassan Javed Chaudhary, Mazhar Rafique, Muhammad Rizwan
Furthermore, members of Pseudomonas undergo an energy-independent and non-metabolic process by which they adsorb heavy metals through the production of biofilm EPS. Polysaccharides, proteins, and nucleic acids act as a protective layer by restricting the diffusion of heavy metals into the biofilm (Chellaiah, 2018; Izrael-Živković et al., 2018). Metalloproteins are a large group of proteins that significantly regulate metal concentration within cells (Coelho et al., 2015). They have the potential to bind Ni, Ag, Zn, Pb, Cd, and Hg with weak bonding (Pereira, 2017). Hence, for heavy metal removal through Pseudomonas, EPS are recommended as surface-active agents because of their extensive capacity (Bramhachari & Nagaraju, 2017). By means of protecting bacterial metabolic processes, metallothioneins also immobilize toxic heavy metals (Naik & Dubey, 2017).
Phytoremediation and detoxification of xenobiotics in plants: herbicide-safeners as a tool to improve plant efficiency in the remediation of polluted environments. A mini-review
Published in International Journal of Phytoremediation, 2020
Daniele Del Buono, Roberto Terzano, Ivan Panfili, Maria Luce Bartucca
Very often, the biosynthesis of metal-binding peptides has a central role in HMs tolerance and detoxification. The chelation of HMs takes place in the cytosol (Hall 2002) and is mostly performed by two heavy metal-binding ligands, i.e. phytochelatins (PCs) and metallothioneins (MTs) (Cobbet and Goldsbrough 2002). PCs are molecules rich of glutathione (GSH), a tripeptide composed of cysteine (Cys), glutamate (Glu) and glycine (Gly). The PCs biosynthesis is carried out by some specific enzymes, the phytochelatin synthases (PCS) (Sharma et al.2016). The function of PCs is to reduce the HMs toxicity to cells, binding different metals and metalloids to form metal-PC complexes (Sharma et al.2016), which are then transferred in a stable form into the vacuole by ATP-dependent vacuolar pumps and tonoplast transporters (Hasan et al.2017) (Figure 1). This compartmentalization is one of the most important mechanisms of HMs accumulation and detoxification since the other cellular components/organelles are no longer subjected to their toxic effect (Sharma et al.2016). MTs are low-molecular weight proteins, well-known for their involvement in maintaining HMs homeostasis (Cobbet and Goldsbrough 2002). MTs show a high affinity for HMs for the presence of two cysteine-rich domains, which can strongly bind the metal ions through their sulfhydryl groups (Hasan et al.2017). In relation to the number of Cys residues, MTs can bind a variety of HMs by mercaptide bonds (Leszczyszyn et al.2013). Similar to PCs, the complex metal-MTs can be transferred into the vacuole. A further interesting function of these proteins, which takes place when MTs have been saturated by metals, is to act as ion donors, so as to contribute to the formation of metalloproteins (Sharma et al.2016). Furthermore, MTs are involved in preventing the oxidative damages that can be caused by ROS (see 3.1.2). Finally, some authors also reported that MTs can be involved in the activation of the transcription of oxidative stress related-genes (Sharma et al.2016).