ID 4.3.1.19 DE threonine ammonia-lyase. AN L-serine dehydratase. AN L-threonine deaminase. AN L-threonine dehydratase. AN L-threonine hydro-lyase (deaminating). AN serine deaminase. AN threonine deaminase. AN threonine dehydrase. AN threonine dehydratase. CA L-threonine = 2-oxobutanoate + NH4(+). CC -!- The reaction catalyzed by both types of enzymes involves the initial CC elimination of water to form an enamine intermediate (hence the CC enzyme's original classification as EC 4.2.1.16), followed by CC tautomerization to an imine form and hydrolysis of the C-N bond. CC -!- The latter reaction, which can occur spontaneously, is also be CC catalyzed by EC 3.5.99.10. CC -!- The enzymes from a number of sources also act on L-serine, CC cf. EC 4.3.1.17. CC -!- Formerly EC 4.2.1.16. DR P37946, ILVA_BACSU ; P53607, ILVA_BURM1 ; Q04513, ILVA_CORGL ; DR P04968, ILVA_ECOLI ; P46493, ILVA_HAEIN ; Q9KC63, ILVA_HALH5 ; DR Q02145, ILVA_LACLA ; P66898, ILVA_MYCBO ; Q9X7F1, ILVA_MYCLE ; DR P9WG94, ILVA_MYCTO ; P9WG95, ILVA_MYCTU ; Q9CKJ2, ILVA_PASMU ; DR P20506, ILVA_SALTY ; Q2FF63, ILVA_STAA3 ; Q2FWJ9, ILVA_STAA8 ; DR Q2YUE8, ILVA_STAAB ; Q5HEE0, ILVA_STAAC ; Q99SJ1, ILVA_STAAM ; DR Q7A4H2, ILVA_STAAN ; Q3V7T5, ILVA_STAAR ; Q3V7T4, ILVA_STAAS ; DR Q8NVI8, ILVA_STAAW ; Q5HMF5, ILVA_STAEQ ; Q8CNK9, ILVA_STAES ; DR Q4L7U4, ILVA_STAHJ ; Q49Z16, ILVA_STAS1 ; Q0VCW4, SDHL_BOVIN ; DR P20132, SDHL_HUMAN ; Q8VBT2, SDHL_MOUSE ; P09367, SDHL_RAT ; DR Q96GA7, SDSL_HUMAN ; Q8R238, SDSL_MOUSE ; P25379, STDH_YEAST ; DR A0FKE6, TD1_SOLLC ; P25306, TD2_SOLLC ; P0AGF8, TDCB_ECO57 ; DR P0AGF7, TDCB_ECOL6 ; P0AGF6, TDCB_ECOLI ; P11954, TDCB_SALTY ; DR P0AGF9, TDCB_SHIFL ; Q2FH01, TDCB_STAA3 ; Q2FYJ3, TDCB_STAA8 ; DR Q2YY67, TDCB_STAAB ; Q5HFY5, TDCB_STAAC ; Q99U50, TDCB_STAAM ; DR Q7A5L8, TDCB_STAAN ; Q6GGX0, TDCB_STAAR ; Q6G9C4, TDCB_STAAS ; DR Q8NWQ4, TDCB_STAAW ; Q9AXU4, TD_NICAT ; P31212, TD_SOLTU ; DR Q9ZSS6, THD1_ARATH ; Q39469, THD1_CICAR ; O42615, THDH_BLAAD ; DR O94634, THDH_SCHPO ; P00927, THDH_YEAST ; Q74FW6, TSAL_GEOSL ; DR Q9WYJ1, TSAL_THEMA ; P55664, Y4TJ_SINFN ; //