Tyrosine metabolic enzymes from insects and mammals：A comparative perspective  

作　　者：Christopher John Vavricka Qian Han Prajwalini Mehere Haizhen Ding Bruce M. Christensen and Jianyong Li 

机构地区：[1]Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, BeUing, China [2]Department of Biochemistry, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA [3]Department of Tuberculosis, The Foundation for Medical Research, Mumbai, India, and [4]Department of Pathobiology, University of Wisconsin-Madison, Madison, Wl 53706, USA

出　　处：《Insect Science》2014年第1期13-19,共7页昆虫科学（英文版）

摘　　要：Differences in the metabolism of tyrosine between insects and mammals present an interesting example of molecular evolution. Both insects and mammals possess finetuned systems of enzymes to meet their specific demands for tyrosine metabolites; however, more homologous enzymes involved in tyrosine metabolism have emerged in many insect species. Without knowledge of modem genomics, one might suppose that mammals, which are generally more complex than insects and require tyrosine as a precur sor for important catecholamine neurotransmitters and for melanin, should possess more enzymes to control tyrosine metabolism. Therefore, the question of why insects actually possess more tyrosine metabolic enzymes is quite interesting. It has long been known that insects rely heavily on tyrosine metabolism for cuticle hardening and for innate immune responses, and these evolutionary constraints are likely the key answers to this question. In terms of melanogenesis, mammals also possess a high level of regulation; yet mam malian systems possess more mechanisms for detoxification whereas insects accelerate pathways like melanogenesis and therefore must bear increased oxidative pressure. Our research group has had the opportunity to characterize the structure and function of many key proteins involved in tyrosine metabolism from both insects and mammals. In this mini review we will give a brief overview of our research on tyrosine metabolic enzymes in the scope of an evolutionary perspective of mammals in comparison to insects.Differences in the metabolism of tyrosine between insects and mammals present an interesting example of molecular evolution. Both insects and mammals possess finetuned systems of enzymes to meet their specific demands for tyrosine metabolites; however, more homologous enzymes involved in tyrosine metabolism have emerged in many insect species. Without knowledge of modem genomics, one might suppose that mammals, which are generally more complex than insects and require tyrosine as a precur sor for important catecholamine neurotransmitters and for melanin, should possess more enzymes to control tyrosine metabolism. Therefore, the question of why insects actually possess more tyrosine metabolic enzymes is quite interesting. It has long been known that insects rely heavily on tyrosine metabolism for cuticle hardening and for innate immune responses, and these evolutionary constraints are likely the key answers to this question. In terms of melanogenesis, mammals also possess a high level of regulation; yet mam malian systems possess more mechanisms for detoxification whereas insects accelerate pathways like melanogenesis and therefore must bear increased oxidative pressure. Our research group has had the opportunity to characterize the structure and function of many key proteins involved in tyrosine metabolism from both insects and mammals. In this mini review we will give a brief overview of our research on tyrosine metabolic enzymes in the scope of an evolutionary perspective of mammals in comparison to insects.

关 键 词：arylalkylamine N-acetyltransferase （aaNAT） ENZYMOLOGY L-DOPAdecarboxylase （DDC） MELANOGENESIS tyrosine metabolism 

分 类 号：Q959.8[生物学—动物学] Q517