Structure and properties of the potato chymotrypsin inhibitor.
The potato tubers contain proteins that inhibit serine proteinases and belong to subfamily of potato Kunitz-type proteinase inhibitors (PKPI). New highly purified protein had been isolated from mature potato tubers (Solanum tuberosum L., cv. Zukov's Jubilee). The protein is а single polypeptide chain of molecular, weighing 23 kDa. The 20 N-terminal amino acid residues of the protein were determined by automatic Edman procedure. On the basis of N-terminal sequence structure and the molecular mass it is indicated that the inhibitor is a potato Kunitz-type serine proteinase inhibitor that belongs to group B. It was denoted as PKCI (potato Kunitz-type chymotrypsin inhibitor). The PKCI was able to inhibit chymotrypsin and trypsin with the same degree of effectiveness. It formed equimolar complexes with both enzymes. The protein PKCI is a double-headed proteinase inhibitor and is able to bind simultaneously two molecules of different enzymes. The probable cDNA of the inhibitor, denoted as PKPIJ-B consists of a 579-bp open reading frame, encodes protein out of 193-amino acids with a signal peptide (10 residues), indicating that this protein is synthesized as a preprotein. Deduced amino acid sequence of the cDNA is aligned with the respective sequences of already known PKPI, belonging to group B.
A.N. Bach Institute of Biochemistry of Russian Academy of Sciences, Russian Academy of Sciences, Leninskii prospect 33, 119071 Moscow, Russia. valueva@inbi.ras.ru
Tatiana A
TA
Valueva
Igor A
IA
Parfenov
Tatiana A
TA
Revina
Elena V
EV
Morozkina
Sergeii V
SV
Benevolensky
D000595:Amino Acid Sequence; D001483:Base Sequence; D002918:Chymotrypsin / Q000037:antagonists & inhibitors*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D035281:Plant Tubers / Q000737:chemistry; D011480:Protease Inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D018749:RNA, Plant / Q000235:genetics; D016415:Sequence Alignment; D011198:Solanum tuberosum / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D018076:DNA, Complementary; C053865:Kunitz-type protease inhibitor, plant; D010455:Peptides; D010940:Plant Proteins; D011480:Protease Inhibitors; D018749:RNA, Plant; D002918:Chymotrypsin