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Carbonic anhydrases (CAs) are enzymes that catalyze the interconversion of CO 2 and HCO 3 − . In nature, there are multiple families of CA, designated with the Greek letters α through θ. CAs are ubiquitous in plants, algae and photosynthetic bacteria, often playing essential roles in the CO 2 concentrating mechanisms (CCMs) which enhance the delivery of CO 2 to Rubisco. As algal CCMs become better characterized, it is clear that different types of CAs are playing the same role in different algae. For example, an α-CA catalyzes the conversion of accumulated HCO 3 − to CO 2 in the green alga Chlamydomonas reinhardtii , while a θ-CA performs the same function in the diatom Phaeodactylum tricornutum . In this review we argue that, in addition to its role of delivering CO 2 for photosynthesis, other metabolic roles of CA have likely changed as the Earth’s atmospheric CO 2 level decreased. Since the algal and plant lineages diverged well before the decrease in atmospheric CO 2 , it is likely that plant, algae and photosynthetic bacteria all adapted independently to the drop in atmospheric CO 2 . In light of this, we will discuss how the roles of CAs may have changed over time, focusing on the role of CA in pH regulation, how CAs affect CO 2 supply for photosynthesis and how CAs may help in the delivery of HCO 3 − for other metabolic reactions. [ABSTRACT FROM AUTHOR]

Abstract: We report the synthesis and enzymatic evaluation of potent inhibitors of acetyl-CoA carboxylases (ACCs) containing biphenyl or 3-phenyl pyridine cores. These compounds inhibit both ACC1 and ACC2, or are moderately selective for either enzyme, depending on side chain substitution. Typical activities of the most potent compounds in this class are in the low double-digit to single-digit nanomolar range in in vitro assays using human ACC1 and ACC2 enzymes. [Copyright &y& Elsevier]

Abstract: The role of biotin as cofactor of carboxylases and its importance in metabolic homeostasis are well known. In recent years, different researchers have suggested the participation of biotin as a regulator molecule in the control of gene expression. Biotin-dependent gene expression requires of the transformation of biotin into biotinyl-5′-AMP by holocarboxylase synthetase and the activation of soluble guanylate cyclase and a cGMP-dependent protein kinase. The regulatory role of biotin is responsible for the correct expression of enzymes involved in biotin utilization in human cells. We propose that this mechanism protects the brain from biotin deficiency. [Copyright &y& Elsevier]