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651.
W K Paik J Farooqui A Gupta H T Smith F Millett 《European journal of biochemistry》1983,135(2):259-262
The present observations are the continuation of our earlier study on the physicochemical mechanism of protein-lysine methylation. In this paper the electrophoretic behaviour (pI values) of two chemically modified horse heart cytochromes c at lysine-72 with trifluoromethylphenylcarbamoyl (neutral group) or carboxydinitrophenyl (acidic group) is compared with the enzymatically methylated cytochrome c. The results indicate that although both chemically modified cytochromes c have lower pI values than the unmodified cytochrome c, the enzymatic methylation appears to be much more efficient in lowering the pI values of the protein than the chemical modification. Furthermore, the lowering of the pI value of cytochrome c by enzymatic methylation is highly dependent on the urea concentration. The presence of urea reduces the effect of methylation on the protein molecule and the difference in pI values virtually disappears with the increasing concentration of urea (6 M), which essentially disrupts the protein tertiary structure. 相似文献
652.
Sang Hoon Paik Yong Jae Kim Sang Kyul Han Jean Man Kim Jae Wook Huh Young In Park 《Biotechnology progress》2012,28(6):1517-1525
A formulation with stabilizers replacing albumin was developed for lyophilization of recombinant factor VIII (FVIII), GreenGene F (WHO INN: beroctocog alfa), to achieve stability and eliminate safety issues of blood‐derived albumin. L ‐Arginine (hydrophilic amino acid, positively charged side chain), L ‐glutamic acid (hydrophilic amino acid, negatively charged side chain), and L ‐isoleucine (hydrophobic amino acid, nonpolar) were selected as stabilizers, and the mixture of the three amino acids were optimized. The mixture had results comparative with albumin and other commonly used stabilizers showing good preservation of recombinant FVIII during lyophilization, robust stability with consistently high recovery of FVIIII, very low aggregate formation, and good storage stability without alterations in protein characteristics. In vivo test results showed that the efficacy was maintained and had no signs of toxicity. The study demonstrated that the three amino acid mixture acts as a good stabilizer for lyophilization of recombinant FVIII and as a safe excipient. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012 相似文献
653.
Minjin Kim Myunghee Cho Paik Jiyeong Jang Ying K. Cheung Joshua Willey Mitchell S. V. Elkind Ralph L. Sacco 《Biometrical journal. Biometrische Zeitschrift》2017,59(3):405-419
When analyzing time‐to‐event cohort data, two different ways of choosing a time scale have been discussed in the literature: time‐on‐study or age at onset of disease. One advantage of choosing the latter is interpretability of the hazard ratio as a function of age. To handle the analysis of age at onset in a principled manner, we present an analysis of the Cox Proportional Hazards model with time‐varying coefficient for left‐truncated and right‐censored data. In the analysis of Northern Manhattan Study (NOMAS) with age at onset of stroke as outcome, we demonstrate that well‐established risk factors may be important only around a certain age span and less established risk factors can have a strong effect in a certain age span. 相似文献
654.
655.
Investigations on the chromosomal inversion polymorphism were conducted on a Korean (Taenung) natural population of D. melanogaster
during the period 1978 to 1992. A total of 66 different endemic and cosmopolitan inversions were found on both major chromosome
pairs II and III. Some of them proved to be rare cosmopolitan types (2LKA, 2LNS, 2LF, 2RCy, 3LM, 3RKI, and 3RK), while others
were endemics. The distribution of breakpoints for endemic and rare cosmopolitan inversions are not random along the two autosome
arms.With respect to frequency changes, the 15-year survey revealed that five of the cosmopolitan types (2Lt, 2RNS, 3LP, 3RC,
and 3RMo) exhibit cyclical frequency changes, whereas gene arrangement 3RP shows relatively stable frequencies. Tests for
correlations between gene arrangement frequencies and several climatic variables gave no clear evidence for such relationships.
Only one correlation coefficient out of 64 was statistically significant.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
656.
H D Paik S S Bae S H Park J G Pan 《Journal of industrial microbiology & biotechnology》1997,19(4):294-298
Bacillus thuringiensis subsp tochigiensis HD868 was identified as a bacteriocin producer which exhibited a bactericidal effect against closely related species. This
bacteriocin designated as tochicin, was partially purified by 75% ammonium sulfate precipitation followed by subsequent
dialysis. This partially purified tochicin showed a narrow antibacterial spectrum of activity against most of 20 typical
B. thuringiensis strains and a strain of B. cereus, but not against other bacteria and yeasts tested. The antibacterial activity of tochicin on sensitive indicator cells disappeared
completely by proteinase K treatment (1 mg ml−1), which indicates its proteinaceous nature. Tochicin was very stable throughout the range of pH 3.0–9.0 and was relatively
heat-stable at 90°C, but bacteriocin activity was not detected after boiling for 30 min. The relationship between cell growth
and bacteriocin production was studied in a semi-defined medium. Tochicin activity was detected at the mid-log growth phase,
reached the maximum at the early stationary phase, but decreased after the stationary phase. Direct detection of tochicin
activity on sodium dodecyl sulfate-polyacrylamide gel suggested it has an apparent molecular mass of about 10.5 kDa. Tochicin
exhibited a bactericidal activity against B. thuringiensis subsp thompsoni HD522 in phosphate buffer (pH 7.0).
Received 02 December 1996/ Accepted in revised form 25 August 1997 相似文献