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21.
Benzoyl-L-arginine p-nitroanilide hydrolase (BAPAase), whichhas both endopeptidase and carboxypeptidase activity towardthe Arg-X or Lys-X bond of small peptides [Shibata and Doi (1984)Plant & Cell Physiol. 25: 1421], was purified from riceembryos by ammonium sulfate and polymin fractionations and byion exchange, gel exclusion and hydrophobic chromatographies.The purified enzyme was homogeneous when analyzed by polyacrylamidegel electrophoresis. It was unstable in the absence of surface-activereagents such as Triton X-100. Maximum activity for benzoyl-Largininep-nitroanilide (L-BAPA) or carboxypeptidase activity towardbutoxycarbonyl-Gly-Lys-Leu was obtained at pH 9.0. L-BAPA athigh concentrations inhibited the enzyme's activity. Di-isopropylphosphofluoridate, N-tosyl-L-lysine chloromethyl ketone, leupeptinand antipain, which are specific inhibitors of trypsin, inhibitedBAPAase activity, but soybean and rice bran trypsin inhibitorhad no effect on it. Sulfhydryl reagents strongly inhibitedthe BAPAase activity. (Received May 26, 1984; Accepted August 29, 1984) 相似文献
22.
Chlorella vulgaris 11h cells grown in air enriched with 4% CO2(high-CO2 cells) had carbonic anhydrase (CA) activity whichwas 20 to 90 times lower than that of algal cells grown in ordinaryair (containing 0.04% CO2, low-CO2 cells). The CO2 concentrationduring growth did not affect either ribulose 1,5-bisphosphate(RuBP) carboxylase activity or its Km for CO2. When high-CO2 cells were transferred to low CO2 conditions,CA activity increased without a lag period, and this increasewas accompanied by an increase in the rate of photosynthetic14CO2 fixation under 14CO2-limiting conditions. On the otherhand, CA activity as well as the rate of photosynthetic 14CO2fixation at low 14CO2 concentrations decreased when low-CO2cells were transferred to high CO2 conditions. Diamox, an inhibitor of CA, at 0.1 mM did not affect photosynthesisof low-CO2 cells at high CO2 concentration (0.5%). Diamox inhibitedphotosynthesis only under low CO2 concentrations, and the lowerthe CO2 concentration, the greater was the inhibition. Consequently,the CO2 concentration at which the rate of photosynthesis attainedone-half its maximum rate (Km) greatly increased in the presenceof this inhibitor. When CO2 concentration was higher than 1%, the photosyntheticrate in low-CO2 cells decreased, while that in high-CO2 cellsincreased. Fractionation of the low-CO2 cells in non-aqueous medium bydensity showed that CA was fractionated in a manner similarto the distribution of chlorophyll and RuBP carboxylase. These observations indicate that CA enhances photosynthesisunder CO2-limiting conditions, but inhibits it at CO2 concentrationshigher than a certain level. The mechanism underlying the aboveregulatory functions of CA is discussed.
1This work was reported at the International Symposium on PhotosyntheticCO2-Assimilation and Photorespiration, Sofia, August, 1977 (18).Requests for reprints should be addressed to S. Miyachi, RadioisotopeCentre, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan. (Received December 11, 1978; ) 相似文献
23.
Toshio Sugimoto Tsutomu Kawasaki Tomohiko Kato Robert F. Whittier Daisuke Shibata Yukio Kawamura 《Plant molecular biology》1992,20(4):743-747
A full-length cDNA encoding a subunit of phosphoenolpyruvate carboxylase (PEPC) was isolated from a developing seed expression library of the C3 plant Glycine max. The corresponding mRNA is present at similar levels in leaf, stem, root and developing seed. Two potential start codons exist, and the activity of protein initiated from the first such codon could be subject to regulation by protein kinase. Sequence comparison shows a similar upstream start codon in the case of the Ppc2 gene from Mesembryanthemum crystallinum, previously assumed to lack the sequences necessary for phosphorylation. The soybean encoded protein tends to resemble other C3-type PEPC proteins more closely than those implicated in C4 or crassulacean acid metabolism. 相似文献
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26.
Limnology - In the original publication of the article the sentence under the heading “Primer and probe design” was published incorrectly. The correct sentence is given in this correction. 相似文献
27.
Daisuke Kyogoku 《Population Ecology》2020,62(2):196-206
Reproductive interference is interspecific sexual interactions that are costly to at least one species involved. Although many studies have reported a substantial fitness cost associated with reproductive interference, suggesting its ecological significance, others have not observed reproductive interference in study species. Reproductive interference that incurs a large fitness cost is more likely to occur during secondary contacts than between long-coexisting species. I first explain the rationale underlying this prediction using existing literature. Next, I present a conceptual framework to classify pairs of interacting species into one of four states, defined by the ecological and evolutionary stabilities of the species pairs. I discuss how the stability states of species pairs are likely to change over time, along with changes in the demographic and evolutionary role of reproductive interference. I then perform literature survey to test the prediction that reproductive interference should be more prevalent in secondary contact. Finally, I discuss the implications of the proposed conceptual framework and literature survey result. 相似文献
28.
Human carboxylesterase 1 (hCES1) is an enzyme that plays an important role in hydrolysis of pharmaceuticals in the human liver. In this study, elucidation of the chiral recognition ability of hCES1 was attempted using indomethacin esters in which various chiral alcohols were introduced. Indomethacin was condensed with various chiral alcohols to synthesize indomethacin esters. The synthesized esters were hydrolyzed with a human liver microsome (HLM) solution and a human intestine microsome (HIM) solution. High hydrolytic rate and high stereoselectivity were confirmed in the hydrolysis reaction in the HLM solution but not in the HIM solution, and these indomethacin esters were thought to be hydrolyzed by hCES1. Next, these indomethacin esters were hydrolyzed in recombinant hCES1 solution and the hydrolysis rates of the esters were calculated. The stereoselectivity confirmed in HLM solution was also confirmed in the hCES1 solution. In the hydrolysis reaction of esters in which a phenyl group is bonded next to the ester, the Vmax value of the (R) form was 10 times larger than that of the (S) form. 相似文献
29.
Daisuke Moriyama 《Bioscience, biotechnology, and biochemistry》2020,84(6):1119-1122
ABSTRACTUsing a crude enzyme solution prepared from astigmatid mites, the conversion reaction to (Z,Z)-6,9-heptadecadiene (6,9-C17) using linoleyl aldehyde (LAld) as a substrate was successful. The mass spectrum of the reaction product using 13C-labeled LAld as a substrate could be assigned as 13C-labeled 6,9-C17. Unlike the findings in other species, the decarbonylase derived from mites did not require a coenzyme. 相似文献
30.
Shohei Katsuta Goro Masuda Hyeokjin Bak Akihisa Shinozawa Yoshiaki Kamiyama Taishi Umezawa Daisuke Takezawa Izumi Yotsui Teruaki Taji Yoichi Sakata 《The Plant journal : for cell and molecular biology》2020,103(2):634-644
Given their sessile nature, land plants must use various mechanisms to manage dehydration under water‐deficit conditions. Osmostress‐induced activation of the SNF1‐related protein kinase 2 (SnRK2) family elicits physiological responses such as stomatal closure to protect plants during drought conditions. With the plant hormone ABA receptors [PYR (pyrabactin resistance)/PYL (pyrabactin resistance‐like)/RCAR (regulatory component of ABA receptors) proteins] and group A protein phosphatases, subclass III SnRK2 also constitutes a core signaling module for ABA, and osmostress triggers ABA accumulation. How SnRK2 is activated through ABA has been clarified, although its activation through osmostress remains unclear. Here, we show that Arabidopsis ABA and abiotic stress‐responsive Raf‐like kinases (AtARKs) of the B3 clade of the mitogen‐activated kinase kinase kinase (MAPKKK) family are crucial in SnRK2‐mediated osmostress responses. Disruption of AtARKs in Arabidopsis results in increased water loss from detached leaves because of impaired stomatal closure in response to osmostress. Our findings obtained in vitro and in planta have shown that AtARKs interact physically with SRK2E, a core factor for stomatal closure in response to drought. Furthermore, we show that AtARK phosphorylates S171 and S175 in the activation loop of SRK2E in vitro and that Atark mutants have defects in osmostress‐induced subclass III SnRK2 activity. Our findings identify a specific type of B3‐MAPKKKs as upstream kinases of subclass III SnRK2 in Arabidopsis. Taken together with earlier reports that ARK is an upstream kinase of SnRK2 in moss, an existing member of a basal land plant lineage, we propose that ARK/SnRK2 module is evolutionarily conserved across 400 million years of land plant evolution for conferring protection against drought. 相似文献