TY - JOUR
T1 - Structure and function of human histamine N-methyltransferase
T2 - Critical enzyme in histamine metabolism in airway
AU - Yamauchi, K.
AU - Sekizawa, K.
AU - Suzuki, H.
AU - Nakazawa, H.
AU - Ohkawara, Y.
AU - Katayose, D.
AU - Ohtsu, H.
AU - Tamura, G.
AU - Shibahara, S.
AU - Takemura, M.
AU - Maeyama, K.
AU - Watanabe, T.
AU - Sasaki, H.
AU - Shirato, K.
AU - Takishima, T.
PY - 1994
Y1 - 1994
N2 - In mammals, histamine is inactivated principally by two enzymes: histamine N-methyl-transferase (HMT; EC 2.1.1.8) and diamine oxidase (DAO; EC 1.4.3.6.). The cDNA clone of human HMT (hHMT) has been isolated from a cDNA library of human kidney and its nucleotide, and deduced amino acid sequences have been determined. One clone, phHMT-1, containing an insert of 1.4 kb, was confirmed to encode HMT by transient expression of HMT activity in COS cells. hHMT consists of 292 amino acid residues [relative molecular weight (M(r)) = 33,279] and shares 82% identity with that of rat HMT. Northern blot analysis with hHMT cDNA probe revealed that 1.6-kb HMT mRNA transcript was expressed in the lung, nasal polyps, and kidney. HMT activity was measured in human trachea and bronchi. In addition, the contractile response of isolated human bronchi to histamine was potentiated in the presence of an HMT inhibitor, SKF 91488, but a DAO inhibitor, aminoguanidine, was without effect. These results suggest that HMT plays an important role in degrading histamine and in regulating the airway response to histamine. Therefore, the level of HMT gene expression in human airway may be one of the critical factors determining the airway responsiveness to histamine. In situ chromosomal hybridization demonstrated that human HMT gene was localized in chromosome 1 p32.
AB - In mammals, histamine is inactivated principally by two enzymes: histamine N-methyl-transferase (HMT; EC 2.1.1.8) and diamine oxidase (DAO; EC 1.4.3.6.). The cDNA clone of human HMT (hHMT) has been isolated from a cDNA library of human kidney and its nucleotide, and deduced amino acid sequences have been determined. One clone, phHMT-1, containing an insert of 1.4 kb, was confirmed to encode HMT by transient expression of HMT activity in COS cells. hHMT consists of 292 amino acid residues [relative molecular weight (M(r)) = 33,279] and shares 82% identity with that of rat HMT. Northern blot analysis with hHMT cDNA probe revealed that 1.6-kb HMT mRNA transcript was expressed in the lung, nasal polyps, and kidney. HMT activity was measured in human trachea and bronchi. In addition, the contractile response of isolated human bronchi to histamine was potentiated in the presence of an HMT inhibitor, SKF 91488, but a DAO inhibitor, aminoguanidine, was without effect. These results suggest that HMT plays an important role in degrading histamine and in regulating the airway response to histamine. Therefore, the level of HMT gene expression in human airway may be one of the critical factors determining the airway responsiveness to histamine. In situ chromosomal hybridization demonstrated that human HMT gene was localized in chromosome 1 p32.
KW - bronchoconstriction
KW - chromosome localization
KW - complementary deoxyribonucleic acid cloning
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U2 - 10.1152/ajplung.1994.267.3.l342
DO - 10.1152/ajplung.1994.267.3.l342
M3 - Article
AN - SCOPUS:0028095648
VL - 267
SP - L342-L349
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 1040-0605
IS - 3 11-3
ER -