scholarly journals Carbonic Anhydrases in Photosynthesizing Cells of C3 Higher Plants

Metabolites ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 73 ◽  
Author(s):  
Lyudmila Ignatova ◽  
Natalia Rudenko ◽  
Elena Zhurikova ◽  
Maria Borisova-Mubarakshina ◽  
Boris Ivanov

The review presents data on the location, nature, properties, number, and expression of carbonic anhydrase genes in the photosynthesizing cells of C3 plants. The available data about the presence of carbonic anhydrases in plasma membrane, cytoplasm, mitochondria, chloroplast stroma and thylakoids are scrutinized. Special attention was paid to the presence of carbonic anhydrase activities in the different parts of thylakoids, and on collation of sources of these activities with enzymes encoded by the established genes of carbonic anhydrases. The data are presented to show that the consistent incorporation of carbonic anhydrases belonging to different families of these enzymes forms a coherent system of CO2 molecules transport from air to chloroplasts in photosynthesizing cells, where they are included in organic molecules in the carboxylation reaction. It is discussed that the manifestation of the activity of a certain carbonic anhydrase depends on environmental conditions and the stage of ontogenesis.

2005 ◽  
Vol 83 (7) ◽  
pp. 780-795 ◽  
Author(s):  
Mautusi Mitra ◽  
Catherine B Mason ◽  
Ying Xiao ◽  
Ruby A Ynalvez ◽  
Scott M Lato ◽  
...  

Carbonic anhydrases (CAs) are zinc-containing metalloenzymes that catalyze the reversible interconversion of CO2 and HCO3–. Aquatic photosynthetic organisms have evolved different forms of CO2-concentrating mechanisms to aid Rubisco in capturing CO2 from the surrounding environment. One aspect of all CO2-concentrating mechanisms is the critical roles played by various specially localized extracellular and intracellular CAs. There are three evolutionarily unrelated CA families designated α-, β-, and γ-CA. In the green alga, Chlamydomonas reinhardtii Dangeard, eight CAs have now been identified, including three α-CAs and five β-CAs. In addition, C. reinhardtii has another CA-like gene, Glp1 that is similar to known γ-CAs. To characterize these different CA isoforms, some of the CA genes have been overexpressed to determine whether the proteins have CA activity and to generate antibodies for in vivo immunolocalization. The CA proteins Cah3, Cah6, and Cah8, and the γ-CA-like protein, Glp1, have been overexpressed. Cah3, Cah6, and Cah8 have CA activity, but Glp1 does not. At least two of these proteins, Cah3 and Cah6, are localized to the chloroplast. Using immunolocalization and sequence analyses, we have determined that Cah6 is located to the chloroplast stroma and confirmed that Cah3 is localized to the chloroplast thylakoid lumen. Activity assays show that Cah3 is 100 times more sensitive to sulfonamides than Cah6. We present a model on how these two chloroplast CAs might participate in the CO2-concentrating mechanism of C. reinhardtii. Key words: carbonic anhydrase, CO2-concentrating mechanism, Chlamydomonas, immunolocalization.


1998 ◽  
Vol 25 (6) ◽  
pp. 673 ◽  
Author(s):  
Lyudmila K. Ignatova ◽  
Oleg V. Moskvin ◽  
Alla K. Romanova ◽  
Boris N. Ivanov

Carbonic anhydrase (CA) activities of the mesophyll protoplasts from Pisum sativum L. leaves (plasmalemma CA), the supernatant after thylakoid precipitation (soluble CA), and the washed thylakoids (thylakoid CA) were studied. It was found that the Km (CO2) were 104 mM for the plasmalemma CA, 20 mM for the soluble CA, and 9 mM for the thylakoid CA. The activity of the last differed from the first two in response to the inhibitor acetazolamide by increasing at submicromolar concentrations of inhibitor. pH-dependencies of Km (HCO3-) for soluble CA and thylakoid CA differed in that the former increased as pH increasd from 7.0 to 8.0, while the latter slightly decreased over this pH change. A comparison of the pH-dependencies of the soluble CA and thylakoid CA dehydrase activities expressed in Wilbur-Andersen units demonstrated that, while the activity of soluble CA was unchanged over pH range 6–8, the activity of thylakoid CA had a distinct pH optimum at pH 6.8–7.0. The possible functions of the three forms of CA in the leaf cell of C3 -plants are briefly discussed.


Author(s):  
James Cronshaw ◽  
Jamison E. Gilder

Adenosine triphosphatase (ATPase) activity has been shown to be associated with numerous physiological processes in both plants and animal cells. Biochemical studies have shown that in higher plants ATPase activity is high in cell wall preparations and is associated with the plasma membrane, nuclei, mitochondria, chloroplasts and lysosomes. However, there have been only a few ATPase localization studies of higher plants at the electron microscope level. Poux (1967) demonstrated ATPase activity associated with most cellular organelles in the protoderm cells of Cucumis roots. Hall (1971) has demonstrated ATPase activity in root tip cells of Zea mays. There was high surface activity largely associated with the plasma membrane and plasmodesmata. ATPase activity was also demonstrated in mitochondria, dictyosomes, endoplasmic reticulum and plastids.


2019 ◽  
Vol 25 (39) ◽  
pp. 5266-5278 ◽  
Author(s):  
Katia D'Ambrosio ◽  
Claudiu T. Supuran ◽  
Giuseppina De Simone

Protozoans belonging to Plasmodium, Leishmania and Trypanosoma genera provoke widespread parasitic diseases with few treatment options and many of the clinically used drugs experiencing an extensive drug resistance phenomenon. In the last several years, the metalloenzyme Carbonic Anhydrase (CA, EC 4.2.1.1) was cloned and characterized in the genome of these protozoa, with the aim to search for a new drug target for fighting malaria, leishmaniasis and Chagas disease. P. falciparum encodes for a CA (PfCA) belonging to a novel genetic family, the η-CA class, L. donovani chagasi for a β-CA (LdcCA), whereas T. cruzi genome contains an α-CA (TcCA). These three enzymes were characterized in detail and a number of in vitro potent and selective inhibitors belonging to the sulfonamide, thiol, dithiocarbamate and hydroxamate classes were discovered. Some of these inhibitors were also effective in cell cultures and animal models of protozoan infections, making them of considerable interest for the development of new antiprotozoan drugs with a novel mechanism of action.


2021 ◽  
Vol 14 (7) ◽  
pp. 693
Author(s):  
Kalyan K. Sethi ◽  
KM Abha Mishra ◽  
Saurabh M. Verma ◽  
Daniela Vullo ◽  
Fabrizio Carta ◽  
...  

New derivatives were synthesised by reaction of amino-containing aromatic sulphonamides with mono-, bi-, and tricyclic anhydrides. These sulphonamides were investigated as human carbonic anhydrases (hCAs, EC 4.2.1.1) I, II, IX, and XII inhibitors. hCA I was inhibited with inhibition constants (Kis) ranging from 49 to >10,000 nM. The physiologically dominant hCA II was significantly inhibited by most of the sulphonamide with the Kis ranging between 2.4 and 4515 nM. hCA IX and hCA XII were inhibited by these sulphonamides in the range of 9.7 to 7766 nM and 14 to 316 nM, respectively. The structure–activity relationships (SAR) are rationalised with the help of molecular docking studies.


2019 ◽  
Vol 55 (40) ◽  
pp. 5720-5723 ◽  
Author(s):  
Andrea Angeli ◽  
Marta Ferraroni ◽  
Alessio Nocentini ◽  
Silvia Selleri ◽  
Paola Gratteri ◽  
...  

Epacadostat (EPA), a selective indoleamine-2,3-dioxygenase 1 (IDO1) inhibitor, has been investigatedin vitroas a human (h) Carbonic Anhydrase Inhibitor (CAI).


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