Amylase-trypsin-inhibitors

Contacts with the catalytic residues, in combination with hydrophobic interactions, are also observed in the complex of an insect a-amylase with the Ragi bifunctional a-amylase/trypsin inhibitor (RBI) [174]. Conversely, the mechanism of inhibition of barley a-amylase by the barley a-amylase/subtilisin inhibitor (BASI) did not involve direct contact between inhibitor residues and the catalytic site [175]. The inhibitor sterically blocks the catalytic site, but does not extend into it. A cavity is created, which is occupied by a calcium ion coordinated by water-mediated interactions with the catalytic residues. 

Alam, N., Gourinath, S., Dey, S., Srinivasan, A., and Singh, T. P. (2001). Substrate-inhibitor interactions in the kinetics of a-amylase inhibition by ragi a-amylase/trypsin inhibitor (RATI) and its various N-terminal fragments. Biochemistry 40, 4229M233. 

Campos, F. A. P. and Richardson, M. (1983). The complete amino acid sequence of the bifunctional a-amylase/trypsin inhibitor from seeds of ragi (Indian finger millet, Eleusine coracana Gaertn.). FEBS Lett. 152, 300-304. 

Shivraj, B. and Pattabhiraman, T. N. (1981). Natural plant enzyme inhibitors. Characterization of an unusual alpha-amylase/trypsin inhibitor from ragi (Eleusine coracana, Geartn). Biochem. ]. 193, 29-36. 

Cereal dual function a-amylase/trypsin inhibitor proteins... 

The cereal dual function a-amylase/trypsin inhibitor proteins are cysteine-rich, disulphide-rich, double-headed, 13-16 kDa, dual function inhibitor proteins that inhibit both of the digestion enzymes a-amylase and trypsin [290-325] (Table 11). Thus the Zea (com) member of this family, com Hageman factor inhibitor (CHFI), is a double-headed 14 kDa protein that inhibits a-amylase and the serine proteases trypsin and blood clotting Factor Xlla [323-324] (Table 11). The structures of the bifunctional a-amylase/trypsin inhibitor proteins from Eleusine (ragi) (RBI) [292-295] and Zea (com) (CHFI) [325] have been determined. These proteins are structurally similar to the lipid transfer proteins, being composed of a bundle of 4 a-helices together with a short [3-sheet element connected by loops, the a-amylase- and protease-inhibitory domains being separately located [325]. 

Oryza sativa (Poaceae) [seed] RA5 (14 kDa 10 Cys), RAM (15 kDa 10 Cys) Cereal a-Amylase /Trypsin inhibitor homologue [306]... 

Triticum aestivum (wheat) (Poaceae) Chloroform-methanol soluble proteins CM , CM2, CM3, CM16.CM17 (13-16 kDa 10 Cvs heterotetramers) Cereal a-Amylase /Trypsin inhibitors [308- 311]... 

Table 11. Cereal dual function a-amylase/trypsin inhibitor proteins For details see the legend to Table 4.

Triticum aestivum (wheat) (Poaeeae) CMXl, CMX2, CMX3 (11-15 kDa lOCys) Cereal a-Amylase/Trypsin inhibitor homologues [312]... 

Junker, Y., Zeissig, S., Kim, S. J., Barisani, D., Wieser, H., Leffler, D. Z. V., et al. (2012). Wheat amylase trypsin inhibitors drive intestinal inflammation via activation of toU-Uke receptor 4. Journal Experimental Medicine, 209, 2395-2408. 

Maskos, K, Huber-Wunderlich, M, Glockshuber, R. (19%). RBI, a one-domain alpha-amylase/ trypsin inhibitor with completely independent binding sites. FEBS, Vol. 397, pp. 11-16, ISSN 1742-4658... 

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