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Degradation Processes




Light Scattering and degradation





























From analysis of Mass/Time curve, discover
:

  • does degradation occur?

  • absolute scission rate

  • polymer structure

  • enzyme action

  • degradation mechanism (random, endwise, multiple phases)

 

Examples of degradation process studied:

A. Signatures for time dependent light scattering enzymatic degradation of linear molecules

 

B. New signatures for time-dependent light scattering degradation of branched polymers

C. Proteoglycan monomers & aggregates

 

D. Enzymatic Degradation monitored by SMSLS - Hyaluronate degradation by hyaluronidase

IR/Kc signatures for different concentrations of hyaluronidase used (M. Drenski, W. F. Reed, J. App. Polym. Sci. 2002 , 92, 2724)

 

E. Enzymatic degradation monitored by TDSLS. Enzymatic hydrolysis was monitored in real-time using time dependent static light scattering (TDSLS) for a variety of galactomannans to determine kinetic parameters, investigate enzyme mechanisms, and make deductions concerning the sequentiality of side-chain substitution (J. L. M. S. Ganter; J. C. Sabbi; W. F. Reed,Biopolymers 2001, 59, 226–242).

Top: LS 90° for enzymatic hydrolysis of Mimosa scabrella (Ms) by a-galactosidase. Inset shows LS 90° for enzymatic hydrolysis of Ms by b-mannanase. Also shown is hydrolysis for a b-mannanase./a-galactosidase.  Bottom: Mw,ap and Rg for Moldenhawera floribunda (Mf) and Melanoxylon brauna (Mb), respectively, during the enzymatic hydrolysis with a-galactosidase. In the inset: Mw,ap and Rg of Ms during the enzymatic hydrolysis with b-mannanase.

 

F. Enzymatic degradation monitored by SEC: effects of enzymes on galactomannans samples: raw data and mass distribution (J. L. M. S. Ganter; J. C. Sabbi; W. F. Reed,Biopolymers 2001, 59, 226–242).

Top: (a) Raw SEC chromatograms of Mimosa scabrella (Ms), before enzymatic hydrolysis, after separate enzymatic hydrolysis by b-mannanase and a-galactosidase, and after combined hydrolysis by b-mannanase/a-galactosidase at 25°C. (b) Raw SEC chromatograms of Ms, Moldenhawera floribunda (Mf), and Melanoxylon brauna (Mb) before and after enzymatic hydrolysis by b-mannanase at 25°C. Bottom: Mass distribution of Mb, before and after enzymatic hydrolysis by a-galactosidase

School of Science and Engineering, 201 Lindy Boggs Center, New Orleans, LA 70118 504-865-5764 sse@tulane.edu