Determining the molecular weight distribution from the stress relaxation properties of a melt

1990 ◽  
Vol 34 (6) ◽  
pp. 867-890 ◽  
Author(s):  
W. J. McGrory ◽  
W. H. Tuminello
Keyword(s):  
Molecular Weight ◽  
Stress Relaxation ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Relaxation Properties

Stress relaxation and molecular weight distribution of polymer melts

1971 ◽  
Vol 10 (3) ◽  
pp. 402-407
Author(s):  
G. Ajroldi ◽  
G. Pezzin
Keyword(s):  
Molecular Weight ◽  
Stress Relaxation ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Polymer Melts

Molecular weight distribution by stress relaxation

1958 ◽  
Vol 13 (2) ◽  
pp. 196-197 ◽  
Author(s):  
A.V Tobolsky ◽  
A Mercurio ◽  
K Murakami
Keyword(s):  
Molecular Weight ◽  
Stress Relaxation ◽  
Molecular Weight Distribution ◽  
Weight Distribution

Extraction and Partial Purification of Protease from Bilimbi (Averrhoa bilimbi L.)

2013 ◽  
Vol 10 (2) ◽  
pp. 29
Author(s):  
Normah Ismail ◽  
Nur' Ain Mohamad Kharoe
Keyword(s):  
Molecular Weight ◽  
Protein Content ◽  
Ammonium Sulfate ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Protease Activity ◽  
Protein Concentration ◽  
Temperature Stability ◽  
Partial Purification ◽  
Ammonium Sulfate Precipitation

Unripe and ripe bilimbi (Averrhoa bilimbi L.) were ground and the extracted juices were partially purified by ammonium sulfate precipitation at the concentrations of 40 and 60% (w/v). The collected proteases were analysed for pH, temperature stability, storage stability, molecular weight distribution, protein concentration and protein content. Protein content of bilimbi fruit was 0.89 g. Protease activity of both the unripe and ripe fruit were optimum at pH 4 and 40°C when the juice were purified at 40 and 60% ammonium sulfate precipitation. A decreased in protease activity was observed during the seven days of storage at 4°C. Molecular weight distribution indicated that the proteases protein bands fall between IO to 220 kDa. Protein bands were observed at 25, 50 and 160 kDa in both the unripe and ripe bilimbi proteases purified with 40% ammonium sulfate, however, the bands were more intense in those from unripe bilimbi. No protein bands were seen in proteases purified with 60% ammonium sulfate. Protein concentration was higher for proteases extracted with 40% ammonium sulfate at both ripening stages. Thus, purification using 40% ammonium sulfate precipitation could be a successful method to partially purify proteases from bilimbi especially from the unripe stage. 

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