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1.
We have previously shown that replacing the P1-site residue (Ala) of chicken ovomucoid domain 3 (OMCHI3) with a Met or Lys results in the acquisition of inhibitory activity toward chymotrypsin or trypsin, respectively. However, the inhibitory activities thus induced are not strong. In the present study, we introduced additional amino acid replacements around the reactive site to try to make the P1-site mutants more effective inhibitors of chymotrypsin or trypsin. The amino acid replacement Asp-->Tyr at the P2' site of OMCHI3(P1Met) resulted in conversion to a 35000-fold more effective inhibitor of chymotrypsin with an inhibitor constant (K(i)) of 1. 17x10(-11) M. The K(i) value of OMCHI3(P1Met, P2'Ala) indicated that the effect on the interaction with chymotrypsin of removing a negative charge from the P2' site was greater than that of introducing an aromatic ring. Similarly, enhanced inhibition of trypsin was observed when the Asp-->Tyr replacement was introduced into the P2' site of OMCHI3(P1Lys). Two additional replacements, Asp-->Ala at the P4 site and Arg-->Ala at the P3' site, made the mutant a more effective inhibitor of trypsin with a K(i) value of 1. 44x10(-9) M. By contrast, Arg-->Ala replacement at the P3' site of OMCHI3(P1Met, P2'Tyr) resulted in a greatly reduced inhibition of chymotrypsin, and Asp-->Ala replacement at the P4 site produced only a small change when compared with a natural variant of OMCHI3. These results clearly indicate that not only the P1-site residue but also the characteristics, particularly the electrostatic properties, of the amino acid residues around the reactive site of the protease inhibitor determine the strength of its interactions with proteases. Furthermore, amino acids with different characteristics are required around the reactive site for strong inhibition of chymotrypsin and trypsin. 相似文献
2.
Masayuki Nakamichi 《Primates; journal of primatology》1984,25(2):192-203
Fourteen female Japanese monkeys of the Arashiyama-B group ranging in age from 11 to 29 years were observed to elucidate the
behavioral characteristics of aging monkeys. A positive significant correlation was found between the occurrences of rest
and age, and a negative significant correlation between the occurrences of auto-grooming and age. Younger female monkeys tended
to be in contact with or in proximity to group members, while older female monkeys tended to spend much more time alone. As
for the grooming interactions, younger female monkeys more often groomed others than did older female monkeys. Also, the former
engaged in grooming more frequently than in being groomed, while the latter spent more time in being groomed than in grooming.
The old female monkeys showed no marked decline in rank, but some of them were surpassed by their adult daughters. 相似文献
3.
The cdc6 mutants of Schizosaccharomyces pombe have been classified as being defective in progression through the G2 phase of the cell cycle. We cloned an S. pombe gene that could complement the temperature-sensitive growth of the cdc6-23 mutant. Unexpectedly, the cloned gene was allelic to pol3, which encodes the catalytic subunit of DNA polymerase δ. Integration mapping confirmed that cdc6 and pol3 are identical. The cdc6-23 mutant carries one amino acid substitution in the conserved N3 region of Pol3.
Received: 17 October 1996 / Accepted: 19 November 1996 相似文献
4.
T Miura 《Plastic and reconstructive surgery》1979,63(2):242-244
A method for correction of an adduction contracture of the thumb is presented. Paired flaps provide good cover to the palmar and dorsal sides of the web space. This method produces better cosmetic and functional results than the traditional methods. 相似文献
5.
6.
Glucanase-treatment of yeast cells was shown to increase the glucose fermenting activity, and decrease the sucrose and maltose fermenting activity. Also, lipase–and phospholipase–treatment decreased the fermenting activity on these sugars. However, the effects on the disaccharide fermenting activity could be reversed under various growth conditions of the yeast cells.From these results, structural factors envolved in the transport of fermentable sugars into yeast cells are discussed. 相似文献
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9.
Toda Hideshige; Arima Toshiyuki; Takahashi Masayuki; Ichimura Shun-ei 《Journal of plankton research》1987,9(1):51-63
Ingestion, respiration, and molting loss rates were measuredover the 3 29°C range in Neomysis intermedia. Weightspecific rates of these physiological processes ranged from2 to 140% body C day1 for ingestion, from 2 to 15% bodyC day1 for respiration, and from 0.1 to 5% body C day1for molting loss. All weight-specific rates showed a logarithmicdecrease with a logarithmic increase in body weight, and a logarithmicincrease with a linear increase in temperature below 20 or 25°C.The effect of temperature, however, was different between thephysiological rates, with a large temperature dependency foringestion (Q10 = 2.6 3.9) and molting loss (Q10 = 2.9 3.6) and a moderate temperature dependency for respiration(Q10 = 1.9 2.1). Calculated assimilation efficiencychanged with body size, but was constant over the temperaturerange examined. Allocation of assimilated materials varied witha change in temperature, reflecting the different temperaturedependence between physiological processes. It was deduced thatthe strong temperature dependency of the growth rate in N. intermediaobserved in the previous studies resulted from the large temperatureeffect on ingestion and assimilation rates, superimposed bythe different allocation of assimilated materials.
1Present address: Department of Botany, University of Tokyo,Hongo, Tokyo 113, Japan 相似文献
10.
A novel ATPase is postulated for isolated mitochondria and mitoblasts of rat liver. The enzyme is active in the presence of oligomycin and carboxyatractyloside. It can be distinguished from other well-known mitochondrial and non-mitochondrial ATPases by its insensitivity to common ATPase inhibitors and effectors and by digitonin treatment. The ATPase is localized on the outer side of the inner mitochondrial membrane. It is activated by Mg2+ in the alkaline pH range and exhibits a biphasic kinetics. The novel external ATPase of rat liver mitochondria possesses similar properties with respect to ATP-dependent protease. 相似文献