Properties of a trypsin inhibitor from Job's-tears (Coix lacryma-jobi L. var. Ma-yuen Stapf).

Abstract

A heat stable trypsin inhibitor was found in the bran of soft-shelled job's-tears {Coix lacrymajobi L. var. Ma-yuenStapf) seeds. This inhibitor seemed to be a simple protein, and the molecular weight was about 12,000. Similar to other heat stable trypsin inhibitors, this inhibitor also contained manycysteine or cystine residues in the molecule. This inhibitor inhibited bovine trypsin at the molar ratio of 1 to 2, showing that it was double-headed. Its activity was stable against the change of pH at the range of3 to 1 1 and high temperature of 100°C under certain conditions. However, the degree of heat stability of the inhibitory activity depended highly upon the kind of the solution in which this inhibitor was dissolved.

Purification and Characterization of Proteinase Inhibitors from Wild Soja (Glycine soja) Seeds

“…3B). These observations agree with most of the BBI are stable to pH and heat, [16][17] and Kunitz type inhibitors are more sensitive to heat.…”

Purification, Amino Acid Sequence, and cDNA Cloning of Trypsin Inhibitors from Onion (Allium cepaL.) Bulbs

“…These observations agree with the fact that most of the BBI type inhibitors are quite stable to pH and heat. 5,6,15) Inhibitory property All the inhibitors strongly inhibited trypsin (Fig. 3A).…”

“…3,4) The BBI family inhibitors have a molecular mass of 7 kDa or 14 kDa, and are characterized by the high contents of Cys residues and high stability to heat and extreme pHs. 5,6) They are called double-headed inhibitors, because they bind and inhibit two serine proteinases at two independent reactive sites. 7) In spite of the accumulating information regarding the primary structures of BBI family proteins, there was no report concerning BBI-family trypsin inhibitors from other sources than Leguminosae and Gramineae plants.…”

Molecular Cloning and Functional Expression of cDNA Encoding a Cysteine Proteinase Inhibitor, Cystatin, from Job's Tears (Coix lacryma-jobiL. var.Ma-yuenStapf)

“…A cystatin from Job's tears might strongly inhibit the proliferation of viruses. A trypsin inhibitor in Job's tears 16,17) has been found.…”