Studies on the origin of amylose and amylopectin in starch granules. III. The effect of temperature on enzyme activities and amylose content

1971 ◽  
Vol 49 (10) ◽  
pp. 1787-1792 ◽  
Author(s):  
B. S. Mangat ◽  
N. P. Badenhuizen
Keyword(s):  
Enzyme Activities ◽  
Amylose Content ◽  
Starch Synthesis ◽  
Effect Of Temperature ◽  
Simultaneous Increase ◽  
Starch Granules ◽  
Starch Composition

Starch composition (amylose content) and the activities of starch-synthesizing enzymes were determined in cultures of Polytoma uvella and potatoes kept at various temperatures. In general ADPG-α-glucan glucosyltransferases were much less thermostable in vivo than P- and Q-enzymes. Potato phosphorylase proved to be the most stable enzyme. In Polytoma both P/Q ratio and amylose content decreased at 30 °C, whereas they remained unchanged in potatoes grown at 30 °C. This confirms the results from earlier experiments which indicated that the P/Q ratio is correlated with amylose content, and is also in agreement with the simultaneous increase in amylose percentage and P/Q ratio observed during the development of starch granules in corn endosperm. The results are discussed in relation to the problem of amylose production in starch granules and the importance of phosphorylase in starch synthesis.

scholarly journals In Vitro and In Vivo Digestibility of Native Maize Starch Granules Varying in Amylose Contents

2007 ◽  
Vol 90 (6) ◽  
pp. 1628-1634 ◽  
Author(s):  
Tatsuya Morita ◽  
Yusuke Ito ◽  
Ian Lewis Brown ◽  
Ryuichi Ando ◽  
Shuhachi Kiriyama
Keyword(s):  
Surface Area ◽  
Linear Correlation ◽  
Resistant Starch ◽  
Amylose Content ◽  
Starch Granules ◽  
Gelatinization Temperature ◽  
Maize Starch ◽  
Positive Linear Correlation

Abstract Digestibility of maize starch granules with different amylose content (AL-0, 22, 54, 68, 80, or 90) was investigated. Measurement of the in vivo resistant starch (RS) content of the starches was performed using surgically prepared ileorectostomized rats. The rats were fed a purified diet containing one of the starches at 652.5 g/kg diet. The in vivo RS content was determined based on the fecal starch excretion. The dietary fiber (DF) value increased as a function of the amylose content in the starch and showed a positive linear correlation with the gelatinization temperature of the granules. In contrast, the in vitro RS content was likely to depend on both the surface area and amylose contents of the starch granules. The maximum in vitro RS content was obtained with AL-68 (54.4). In vivo RS content showed a significant correlation with the amount of in vitro RS but not in respect to the DF detected. The in vivo RS content of AL-68 (43.4) was higher than that found in AL-90 (37.8). A profound gap was observed for AL-54 between the amount of DF (6.4) and RS (in vitro = 46.6 and in vivo = 40.9) present. The results suggest that both in vitro and in vivo digestibility of maize starch is affected by the amylose content and surface area of the granules. The current evaluation suggests that the physiological occurrence of RS from maize starch might be predictable by reference to the in vitro RS value.

scholarly journals Starch Synthesis-Related Genes (SSRG) Evolution in the Genus Oryza

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1057
Author(s):  
Karine E. Janner de Freitas ◽  
Railson Schreinert dos Santos ◽  
Carlos Busanello ◽  
Filipe de Carvalho Victoria ◽  
Jennifer Luz Lopes ◽  
...  
Keyword(s):  
Active Sites ◽  
Grain Quality ◽  
Amylose Content ◽  
Starch Synthesis ◽  
Asian Rice ◽  
New Information ◽  
Grain Starch ◽  
In The Wild ◽  
Starch Composition ◽  
Analysis Of Variation

Cooking quality is an important attribute in Common/Asian rice (Oryzasativa L.) varieties, being highly dependent on grain starch composition. This composition is known to be highly dependent on a cultivar’s genetics, but the way in which their genes express different phenotypes is not well understood. Further analysis of variation of grain quality genes using new information obtained from the wild relatives of rice should provide important insights into the evolution and potential use of these genetic resources. All analyses were conducted using bioinformatics approaches. The analysis of the protein sequences of grain quality genes across the Oryza suggest that the deletion/mutation of amino acids in active sites result in variations that can negatively affect specific steps of starch biosynthesis in the endosperm. On the other hand, the complete deletion of some genes in the wild species may not affect the amylose content. Here we present new insights for Starch Synthesis-Related Genes (SSRGs) evolution from starch-specific rice phenotypes.

Effects of high temperature on grain growth and on the metabolites and enzymes in the starch-synthesis pathway in the grains of two wheat cultivars differing in their responses to temperature

2003 ◽  
Vol 30 (3) ◽  
pp. 291 ◽  
Author(s):  
Morteza Zahedi ◽  
Rajinder Sharma ◽  
Colin F. Jenner
Keyword(s):  
High Temperature ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Soluble Starch ◽  
Starch Synthase ◽  
Effect Of Temperature ◽  
The Difference

The effects of a sustained period of moderately high temperature were evaluated on the availability of substrate and the activity of starch synthase (ADP-glucose: 1,4-α-D-glucan 4-α-D-glucosyltransferase, EC 2.4.1.21) in the developing grains of two wheat Triticum aestivum L. cultivars differing in their tolerance to high temperature. Final grain weight was reduced by 33% in the least sensitive (cv. Kavko) and by 40% in the most sensitive (cv. Lyallpur) cultivar as post-anthesis temperature was raised from 20/15°C (day/night) to 30/25°C. The difference in the response of the two cultivars was mainly due to changes in the rate of grain filling at high temperature. The response of the rate of grain filling at high temperature, and the differential effects on the two cultivars, did not seem to be explained by an effect of temperature on the supply of assimilate (sucrose) or on the availability of the substrate for starch synthesis (ADP-glucose) in the grains. In vitro, but not in vivo, the differential responses of the efficiency (Vmax/Km) of soluble starch synthase in the two cultivars to an increase in temperature were associated with differences in the temperature sensitivity of grain filling. In vivo, the most remarkable difference between the two varieties was in the absolute values of the efficiency of soluble starch synthase, with the most tolerant cultivar having the highest efficiency.

scholarly journals Changes of physicochemical properties and correlation analysis of common buckwheat starch during germination

Fagopyrum ◽  
1970 ◽  
Vol 36 (2) ◽  
pp. 43-50 ◽  
Author(s):  
Licheng Gao ◽  
Meijuan Xia ◽  
Zhonghao Li ◽  
Pengke Wang ◽  
Meng Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Correlation Analysis ◽  
Physicochemical Properties ◽  
Amylose Content ◽  
Pasting Properties ◽  
Fat Content ◽  
Starch Granules ◽  
Common Buckwheat ◽  
Particle Structure ◽  
Starch Composition

In order to clarify the physicochemical properties of starch during germination of common buckwheat, Xinong9976 was selected as the experimental material to study the main nutrients, particle structure, particle size distribution, transparency, aging value, pasting properties and the correlation between pasting properties and starch composition and main nutrients. The results showed that main nutrients were significantly different. The diameter of starch granules ranged from 2.36 to 8.89.m, and the shapes of starch granules were irregular with obvious holes and cracks on the surface. There were significant differences in starch transparency, aging value and pasting properties at different germination stages. Peak viscosity, through viscosity and final viscosity of germinated common buckwheat was significantly positive correlated with amylopectin content (P < 0.05) and breakdown, final viscosity and setback were significantly negatively correlated with amylose content (P < 0.05). The correlation analysis of starch pasting properties and main nutrients showed that breakdown, setback and crude fat content were significantly negatively correlated (P < 0.01), peak viscosity, through viscosity and final viscosity were significantly negatively correlated with crude fat content (P < 0.05), while the starch pasting properties had no significant correlation with other nutrients.Received: April 14, 2019; accepted: June 8, 2019Key words: common buckwheat, germination, physicochemical properties, starch

Applicability of Instability Index for In vitro Protein Stability Prediction

2019 ◽  
Vol 26 (5) ◽  
pp. 339-347 ◽  
Author(s):  
Dilani G. Gamage ◽  
Ajith Gunaratne ◽  
Gopal R. Periyannan ◽  
Timothy G. Russell
Keyword(s):  
Protein Stability ◽  
Caulobacter Crescentus ◽  
Effect Of Temperature ◽  
Instability Index ◽  
Dipeptide Composition ◽  
Experimental Conditions ◽  
The Stability ◽  
Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

Effect of Temperature during Grain Filling Stage on Endosperm Structure and Apperance Quality of Aromatic Rice

2012 ◽  
Vol 460 ◽  
pp. 286-289 ◽  
Author(s):  
Zhen Jiang Xu ◽  
Li Zhong Xiao ◽  
Hong Liu ◽  
Yong Hao Ren ◽  
Zhi Lin Li
Keyword(s):  
Grain Filling ◽  
Effect Of Temperature ◽  
Rice Grain ◽  
Aromatic Rice ◽  
Starch Granules ◽  
Filling Stage ◽  
Appearance Quality ◽  
Endosperm Structure ◽  
Grain Filling Stage

Based on the experiment of two inbred aromatic rice varieties and one hybrid aromatic rice line treated under four different temperatures( daymean temperature 21°C, 23°C, 26°C and 30°C respectively) during grain filling stage in phytotrons, the shape and arrangement of endosperm starch granules in rice grain transection were observed by scanning electron microscope and the related characteristics of rice grain qualities of chalky percent and chalkiness were analyzed at the same time. The results showed that under the lower temperature( daymean temperature21°C and 23°C), many large compound starch granules with clear angulars packed together regularly without significant natural gaps bewteen starch granules in the tansectional endosperm. However, with the increase of temperature, starch granules in the transectional endosperm were changed from regularly shaped and closely and orderly arranged to various shaped and chaoticly arranged with obvious natural gaps between starch granules, which was closely consistent with the poorer appearance quality under the higher temperature, which indicated that the endosperm structure is closely related with appearance quality of aromatic rice.

Starch Accumulation and Enzyme Activities Associated with Starch Synthesis in Maize Kernels

2007 ◽  
Vol 6 (7) ◽  
pp. 808-815 ◽  
Author(s):  
Hai-yan ZHANG ◽  
Shu-ting DONG ◽  
Rong-qi GAO ◽  
Qing-quan SUN
Keyword(s):  
Enzyme Activities ◽  
Starch Synthesis ◽  
Starch Accumulation ◽  
Maize Kernels

scholarly journals Enzymatic activity in turkey, duck, quail and chicken liver microsomes against four human cytochrome P450 prototype substrates and aflatoxin B1

2011 ◽  
Vol 1 (1) ◽  
pp. 4 ◽  
Author(s):  
Hansen W. Murcia ◽  
Gonzalo J. Díaz ◽  
Sandra Milena Cepeda
Keyword(s):  
Cytochrome P450 ◽  
Aflatoxin B1 ◽  
Enzyme Activities ◽  
High Performance ◽  
Biochemical Characterization ◽  
Liver Microsomes ◽  
Cytochrome P450 Enzymes ◽  
Catalytic Rate

Cytochrome P450 enzymes (CYP) are a group of monooxygenases able to biotransform several kinds of xenobiotics including aflatoxin B1 (AFB1), a highly toxic mycotoxin. These enzymes have been widely studied in humans and others mammals, but there is not enough information in commercial poultry species about their biochemical characteristics or substrate specificity. The aim of the present study was to identify CYPs from avian liver microsomes with the use of prototype substrates specific for human CYP enzymes and AFB1. Biochemical characterization was carried out in vitro and biotransformation products were detected by high-performance liquid chromatography (HPLC). Enzymatic constants were calculated and comparisons between turkey, duck, quail and chicken activities were done. The results demonstrate the presence of four avian ortholog enzyme activities possibly related with a CYP1A1, CYP1A2, CYP2A6 (activity not previously identified) and CYP3A4 poultry orthologs, respectively. Large differences in enzyme kinetics specific for prototype substrates were found among the poultry species studied. Turkey liver microsomes had the highest affinity and catalytic rate for AFB1 whereas chicken enzymes had the lowest affinity and catalytic rate for the same substrate. Quail and duck microsomes showed intermediate values. These results correlate well with the known in vivo sensitivity for AFB1 except for the duck. A high correlation coefficient between 7-ethoxyresorufin-Odeethylase (EROD) and 7-methoxyresorufin- O-deethylase (MROD) activities was found in the four poultry species, suggesting that these two enzymatic activities might be carried out by the same enzyme. The results of the present study indicate that four prototype enzyme activities are present in poultry liver microsomes, possibly related with the presence of three CYP avian orthologs. More studies are needed in order to further characterize these enzymes.

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