Carboxylesterases tissue distribution

Urinary proteins were analyzed by SDS-polyacrylamide gel electrophoresis (PAGE), and a 70-kDa protein was identified as the major component of cat urine (Fig. 4.1 A). Comparative analysis of urinary proteins in several other mammals such as humans, mice, dogs, and cattle did not detect a 70-kDa protein. Therefore, the 70-kDa protein was purified from cat urine and characterized by biochemical methods (Miyazaki, Kamiie, Soeta, Taira and Yamashita 2003). Analysis of tissue distribution indicated that the 70-kDa protein is expressed in the kidney in a tissue-specific manner and secreted from the proximal straight tubular cells of the kidney into the urine (Fig. 4.IB). A full-length cDNA for a 70-kDa protein was cloned from a cat kidney cDNA library. The cDNA clone encoded a polypeptide of 545 amino acid residues. The deduced amino acid sequence shared 47% identity with cat carboxylesterase (CES, EC 3.1.1.1), and contained both the CES family protein motif (EDCLY) and a conserved active site motif (GESAG) associated with... 

R. A. Dean, J. Zhang, M. R. Brzezinski, W. F. Bosron, Tissue Distribution of Cocaine Methyl Esterase and Ethyl Transferase Activities Correlation with Carboxylesterase Protein , J. Pharmacol. Exp. Ther. 1995, 275, 965 - 971. 

B. Ab, T. Imamura, Characteristics Of Rat Lung Carboxylesterases/Amidases , Proc. West. Pharmacol. Soc. 1985, 28, 319-322 B. Ab, S. Kaur, Mammaban Tissue Acet-ylsabcybc Acid Esterase(s) Identification, Distribution and Discrimination from Other Esterases , J. Pharmacol. Exp. Then 1983, 226, 589 - 594. 

Differences among species in distribution patterns of histological changes may be caused by species variations in the distribution in the nasal epithelium of chemical-metabolizing enzymes. For example, in rats exposed to methyl methacrylate, nasal lesions were shown to be caused by the carboxylesterase mediated metabolism of methyl methacrylate to methacrylic acid, an irritant and corrosive metabohte. The distribution of these enzymes in the nasal tissues of man, rat, and hamster indicated a lower rate of metabolism in man compared to rat and hamster, suggesting a lower sensitivity to methacrylate in humans (Mainwaring et al. 2001). 

Enzymes with carboxylesterase and amidases activity are widely distributed in the body, occurring in many tissues and in both microsomal and soluble fractions. They catalyze the following general reactions ... 

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