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Purification and characteristics of an endogenous alpha-amylase and trypsin inhibitor from wheat seeds'*2 J. R. WARCHALEWSKIThe bifunctional endogenous alpha-amylase and trypsin inhibitor was purified 151-fold from a crude extract of wheat grain by (NH,),SO, fractionation, ion exchange chromatography and gel filtration. The inhibitor coded A/T-WI was an albumin protein, relatively heat stable with a molar mass of 23233 g/mol and optimum activity towards native alpha-amylase and trypsin at pH 5.1 and 7.1,respectively. Amino acid analysis indicated the presence of about 15 half-cystine residues per mole. The protein was homogeneous as assessed by polyacrylamide gel electrophoresis. In the presence of detergent the inhibitor was dissociated into two subunits. A "double head" in nature the inhibitor was almost inactive in the presence of detergent with reducing agent. At neutral pH over 80 % of inhibitor was adhered to wheat starch granules. IntroductionRecently the present state of research on alpha-amylase inhibitors in cereals was reviewedThe first ever indication of inhibition of wheat endogenous alpha-amylase caused by soluble protein of albumin type isolated and partially purified from Durum wheat (Triticum durum) was reported by WARCHALEWSKI [2]. In more recent studies WARCHALEWSKI et al.[3--61 reported relatively heat stabile inhibitors of wheat alpha-amylases in different winter wheat and malted winter wheat cultivar (cv.). Later on alpha-amylase inhibitors were isolated from various types of wheat grain and tested for their activity against alpha-amylases from various sources [7]. These inhibitors were highly active against alpha-amylase from the same source but showed decreased activity towards alpha-amylases from other types of wheat, indicating a highly specific interaction between alpha-amylase and its natural protein inhibitor.Purothionins have been implicated also as inhibitors of wheat alpha-amylase [S]. Only recently the presence of an endogenous alpha-amylase inhibitor was confirmed in various cereal grains including wheat by an immunochemical method [9].None of the mentioned above native alpha-amylase inhibitors from wheat kernels has been purified to the homogeneous protein with the exception of a bifunctional wheat inhibitor of an endogenous alpha-amylase and subtilisin [lo]. On the other hand, most research ill.Presented in part at 17 th FEBS Meeting Berlin (West), August 24-29, 1986. This research was carried out in part at the University of Maiduguri, Nigeria. 1016Die Nahrung 31 (1987) 10 on alpha-amylase inhibitors has been restricted to a family of albumins isolated from wheat seed [l 11. These albumins d o not have inhibitory activity against cereals alpha-amylases [12].The current investigation describes the purification from albumin fraction, amino acid composition. and some physicochemical properties of the bifunctional alpha-amylase/ trypsin inhibitor from wheat seed. Some parameters affecting the enzyme-inhibitor interaction will be discussed. Materials and methods Puri/fi'cofiori (?/...

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Grain of winter wheat cv. Begra was investigated for changes in some physical and chemical properties resulting from direct influence of microwave heating on grain harvested in three subsequent generations of crops at Plant Breeding Station DANKO in Choryn, Poland. Wheat grain samples tested immediately after microwave treatment with the highest grain temperature at 79 and 98°C showed a statistically significant decrease in moisture content (MC), thousand kernel weight (TKW), single kernel weight (SKW), single kernel diameter (SKD), and hardness index (HI), with the exception of grain samples M‐120 and M‐180, respectively, where statistically significant increases in HI and SKD were observed. Indirect effect of microwaves caused statistically significant fluctuation of the total protein content (TPC), TKW, single kernel moisture content (SKM), HI, SKW, and SKD in all three wheat grain crops in relation to their control samples. This indicates that the studied physicochemical properties of grain were affected by microwave rays not only directly but also indirectly.

Grain of six winter and spring wheat varieties differing in baking quality were included in the study. A number of technological analyses were performed. Albumins, globulins and gliadins were washed out. LCP cation of inhibitory activities of alpha-amylases in extracted proteins against enzymes of various origin were tested and compared to baking quality of the wheat grain. Also, the location of endogenous amylase activity in extractable proteins was compared to baking quality of the studied varieties. A certain correlation between the incidence of hieher inhibition activity against alpha-amylase of Sitopkilrir rrnnnriw L. and good baking quality has been found. However, location ofendogenous alpha-amylases in grain seems to be a better criterion classifying varieties according to their baking quality. So-called baking varieties have higher and only activity of endogenous alpha-amylases located in albumin and gliadin fractions, whereas in poorest, "non-baking" varieties this activity is also located in the globulin fraction.