The mature form of human ornithine transcarbamylase
(OTCase) is a trimeric protein, composed of three identical
subunits of 322 amino acids in length.
OTCase catalyzes the formation of citrulline and inorganic
phosphate from carbamylphosphate and ornithine.
The human OTCase sequence (GenBank NP_00422 GI:38788445)
is as follows:
1
MLFNLRILLN
NAAFRNGHNF MVRNFRCGQP LQNKVQLKGR DLLTLKNFTG EEIKYMLWLS
61 ADLKFRIKQK GEYLPLLQGK SLGMIFEKRS TRTRLSTETG FALLGGHPCF
LTTQDIHLGV
121 NESLTDTARV LSSMADAVLA RVYKQSDLDT LAKEASIPII NGLSDLYHPI
QILADYLTLQ
181 EHYSSLKGLT LSWIGDGNNI LHSIMMSAAK FGMHLQAATP KGYEPDASVT
KLAEQYAKEN
241 GTKLLLTNDP LEAAHGGNVL ITDTWISMGQ EEEKKKRLQA FQGYQVTMKT
AKVAASDWTF
301 LHCLPRKPEE VDDEVFYSPR SLVFPEAENR KWTIMAVMVS LLTDYSPQLQ
KPKF
The protein is synthesized as a 354 amino acid
long preprotein in the cytoplasm. Upon import into the
mitochondria, the first 32 amino acids (shown in magenta)
are cleaved to produce the mature protein.