Sławomir Orzechowski

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Starch is the most abundant storage carbohydrate produced in plants. The initiation of transitory starch synthesis and degradation in plastids depends mainly on diurnal cycle, post-translational regulation of enzyme activity and starch phosphorylation. For the proper structure of starch granule the activities of all starch synthase isoenzymes, branching(More)
Alanine aminotransferase (AlaAT, EC 2.6.1.2) and glycine aminotransferase (GlyAT, EC 2.6.1.4), two different enzymes catalyzing transamination reactions with L-alanine as the amino-acid substrate, were examined in maize in which alanine participates substantially in nitrogen transport. Preparative PAGE of a partially purified preparation of(More)
This study describes the development of a new colorimetric assay to determine aromatic amino acid aminotransferase (ArAT) activity. The assay is based on the transamination of l-tryptophan in the presence of 2-oxoglutarate, which yields indole-3-pyruvate (IPyA). The amount of IPyA formed was quantified by reaction with the Salkowski reagent. Optimized assay(More)
Barley biotypes from the world collection differ in their storage protein content even till 200 %. This is the first report including results of the research, in which the structure of grains containing different amount of protein was tested to explain this difference. The endosperm was investigated using scanning electron microscopy. The structure of the(More)
During starch metabolism, the phosphorylation of glucosyl residues of starch, to be more precise of amylopectin, is a repeatedly observed process. This phosphorylation is mediated by dikinases, the glucan, water dikinase (GWD) and the phosphoglucan, water dikinase (PWD). The starch-related dikinases utilize ATP as dual phosphate donor transferring the(More)
Water-deficit is accompanied by an increase in proteolysis. Phytocystatins are plant inhibitors of cysteine proteinases that belong to the papain and legumain family. A cDNA encoding the protein inhibitor TrcC-8 was identified in the vegetative organs of triticale. In response to water-deficit, increases in the mRNA levels of TrcC-8 were observed in leaf(More)
Storage proteins of cereal seeds are processed during accumulation and degraded during germination primarily by cysteine proteinases. One of the mechanisms controlling the activity of these enzymes is the synthesis of specific inhibitors named phytocystatins. Here we present the complete gene sequence of a triticale ( × Triticosecale Wittm.) phytocystatin,(More)
Phytocystatins are a group of proteins with significant potential to regulate activities of cysteine proteinases of native and pest/pathogen origins. The two-domain triticale (x Triticosecale Wittm.) phytocystatin TrcC-8 was characterized in this study. This protein belongs to the second group of phytocystatins and contains all the conserved sequences and(More)
A loss of dehydration tolerance in wheat seedlings on the fifth day following imbibition is associated with a disturbance in cellular redox homeostasis, as documented by a shift of the reduced/oxidized glutathione ratio to a more oxidized state and a significant increase in the ratio of protein thiols to the total thiol group content. Therefore, the(More)
The intracellular distribution of alanine aminotransferase (AlaAT, EC 2.6.1.2) activity with L-alanine and 2-oxoglutarate as a substrates in maize whole leaf extract and bundle sheath cells was studied. After isolation of the mitochondrial-peroxisomal fraction, mitochondria and peroxisomes were separated by centrifugation on a linear 40–52 % (w/w) sucrose(More)