Comparative Study on Amino Acid Sequences of Kunitz-Type Soybean Trypsin Inhibitors, Tia, Tib, and Tic1

Abstract

The amino acid sequences of three variants of the Kunitz-type trypsin inhibitors, Tia, Tib, and Tic, obtained from some cultivars of soybean were determined by conventional methods. All three inhibitors consisted of 181 amino acid residues. The differences in the amino acid sequences are as follows: Tia E12 G55 Y62 H71 S74 M114 L120 P137 L176; Tib S F N R V I T V; Tic E. The amino acid sequences of Pro(60)-Ser(61) and Asp(154)-Asp(155)-Gly(156)-His(157) of Tia reported previously (Koide & Ikenaka (1973) Eur. J. Biochem. 32, 417-431) were amended to Ser(60)-Pro(61) and His(154)-Asp-Asp-Gly(157), respectively.

Primary structure of cathepsin D inhibitor from potatoes and its structure relationship to soybean trypsin inhibitor family

“…All these data, together with the knowledge of the peptides resulting from chymotryptic digestion of PDI, enabled us to derive the primary structure of PDI shown in fig.3. This structure is homologous to the structure of soybean trypsin inhibitor (STI) [21] and to that of the related winged bean trypsin inhibitor (WTI) [22]. From sequence homologies it was recently shown that the doubleheaded a-amylase/subtilisin inhibitor from barley [23] as well as the inhibitors of cysteine proteinases from potatoes [24] also belong to the same structural superfamily.…”

Change in Activity of Soybean Trypsin Inhibitor by Removal of C-terminal Amino Acid Residues during Seed Germination

“…T{a and Tic inhibited the activity of bovine trypsin at 1989), and to inhibit digestive proteolytic enzymes of a ratio 1 : 1 when an enzyme concentration of 2.18 X 1Q-8 M mammals and insects (Green and Lyman, 1972). The was used for the titration (Kim et al, 1985). By contrast real role of KSTI is still not fully understand.…”

A frameshift mutation prevents Kunitz trypsin inhibitor mRNA accumulation in soybean embryos.

“…The soybean genome contains at least 10 distinct DNA sequences that are complementary to Kunitz trypsin inhibitor cDNA plasmids (Jofuku, 1987; berg, 1989), and produces a more prevalent Kunitz trypsin inhibitor mRNA (Figures 2 and 3). Comparison of the KTi3 gene translated protein sequence (Figure 8) with that of the Kunitz trypsin inhibitor Ti"allelic form (Kim et al, 1985) indicates that they are identical. The translated protein sequence has 24 amino acids at the amino terminus and 11 amino acids at the carboxy terminus that are not present in the mature Kunitz trypsin inhibitor protein.…”