The amino acid sequence of a cereal Bowman‐Birk type trypsin inhibitor from seeds of Jobs' tears (Coix lachryma‐jobi L.)

Abstract

The major trypsin inhibitor from seeds of Jobs' tears (Coix lachryma-jobO was purified by heat treatment, fractional precipitation with (NH4)2SO4, ion-exchange chromatography on DEAE-Sepharose, gel-filtration on Sephadex G-75 and preparative reverse-phase HPLC. The complete amino acid sequence was determined by analysis of peptides derived from the reduced and S-carboxymethylated protein by digestion with trypsin, chymotrypsin and the S. aureus V8 protease. The polypeptide contained 64 amino acids with a high content of cysteine. The sequence exhibited strong homology with a number of Bowman-Birk inhibitors from legume seeds and similar proteins recently isolated from wheat and rice.

Proteinase inhibitors and their function in plants: A review

“…Inhibitors with similar characteristics were isolated from wheat [17], barley [101], rice [102], and certain other plants of the family of cereal grains (Gramineae) [103][104][105]. Inhibitors from cereals are represented by proteins of two groups, I and II [17].…”

The amino acid sequence and reactive site of a single-headed trypsin inhibitor from wheat endosperm

“…are trypsin inhibitors 11-4 and I-2b from wheat (Triticum aestivum) germ (Odani et al, 1986); BBI-M is Bowman-Birk trypsin inhibitor-related protein from maize (Zea mays L.) seedlings (Eckelkamp et al, 1993); COIX is trypsin inhibitor from Jobs' tears (Coix lachryma-jobi L) seeds (Ary et al, 1988); RBTI and RBTI* are rice bran (Oryza sativa) trypsin inhibitor residues 1-69 and 70-133, respectively ; BRTI and BRTI* are barley rootlet (Hordeum disticum) trypsin inhibitor residues 1-62 and 63-124, respectively ; FMTI-II is trypsin inhibitor from seeds of foxtail millet (Setaria italica) (Tashiro et al, 1990); SBI C-II (Odani and Ikenaka, 1977), SBI D-II (Odani and Ikenaka, 1978), and BBI (Odani and Ikenaka, 1972) are proteinase inhibitors C-II, D-II, and Bowman-Birk from soybean (Glycine max); GBI-II' is trypsin inhibitor II' from garden beans (Phaseolus vulgaris) (Wilson and Laskowski, 1975); APII-A' (Kiyohara et al, 1981) and AB I (Ishikawa et al, 1979) are proteinase inhibitors I-A' and I from adzuki bean (Vigna angularis), subspecies "Dainagon" and "Takara", respectively; MBTI is proteinase inhibitor from seeds of mung bean (Vigna radiata) (Zhang et al, 1982); CpTI flV is protease inhibitor flV from cowpea (Vigna unguiculata Walp.) seeds (Hilder et al, 1989); LBI-IV' is proteinase inhibitor IV' from lima bean (Phaseolus lunatis) (Stevens et aL, 1974); MAI DE-3 and MAI DE-4 are protease inhibitors DE-3 and DE-4 from Macrotyloma axillare seeds (Joubert et al, 1979); PI A-II and PI B-II are trypsin-chmotrypsin inhibitors A-II and B-II from peanut (Arachis hypogaea) (Norioka and Ikenaka, 1983); LCI-DE-4 is proteinase inhibitor DE-4 from seeds of apple-leaf (Lonchocarpus capassa) (Joubert, 1984); PAl DE-I is proteinase inhibitor DE-1 from Pterocarpus angolensis (Kiaat) (Joubert, 1982); VAI is proteinase inhibitor from Vicia angustifolia L. (var.…”

“…However, since 1985 this type of inhibitors has been found also in leaves (Brown et al, 1985) as well as in grains (Odani et al, 1986;Tashiro et al, 1987;Ary et al, 1988;Poerio et al, 1989;Tashiro et al, 1990) and other tissues (Nagasue et al, 1988;Eckelkamp et al, 1993) of a limited number of cereals. The first extensive study on wheat trypsin inhibitors of the Bowman-Birk type goes back to 1986 when Odani and co-workers reported the partial sequences of two trypsin inhibitors isolated from germ tissue and codenamed WGTI 11-4 and WGTI I-2b.…”

“…Such structural and kinetic properties have justified the definition of doubleheaded inhibitors for these molecules. Recently, sequence analysis and homology studies carried out on trypsin inhibitors isolated from a number of cereals (Odani et al, 1986;Tashiro et al, 1987;Ary et al, 1988;Nagasue et al, 1988;Tashiro et al, 1990;Eckelkamp et al, 1993) clearly demonstrated that Bowman-Birk type inhibitors are present in gramineous as well as in leguminous plants. The cereal Bowman-Birk type inhibitors, isolated up to now, are all active toward trypsin and have been divided into two classes, type I and II.…”

“…The cereal Bowman-Birk type inhibitors, isolated up to now, are all active toward trypsin and have been divided into two classes, type I and II. Type II inhibitors include proteins consisting of a single unit of Bowman-Birk type inhibitor such as wheat germ trypsin inhibitor 11-4 (Odani et al, 1986), Job's tears trypsin inhibitor Coix (Ary et al, 1988), and maize seedlings trypsin inhibitor (Eckelkamp et al, 1993). They exhibit a molecular weight of about 7 kD and present only one reactive site (single-headed inhibitors), which corresponds to the first reactive site of the homologous inhibitors isolated from leguminous seeds and which is located at the N-terminal region of the molecule.…”