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Affinity properties of phosvitin: Interaction of phosvitin with serine hydroxymethyl transferase

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Title Affinity properties of phosvitin: Interaction of phosvitin with serine hydroxymethyl transferase
 
Creator Lakhey, H V
Rao, A G Appu
Prakash, V
Krishnaswamy, P R
Savithri, H S
Rao, N Appaji
Ramadoss, C S
 
Description 69-76
The affinity of phosvitin with serine hydroxymethyl transferase
(SHMT), an acidic multi-subunit protein, was evaluated by measurements of
enzyme activity, sedimentation velocity, steady-state fluorescence, circular
dichroism and kinetic thermal stability. While the presence of phosvitin had no
effect on the SHMT activity, the sedimentation coefficient of SHMT increased
from 8.7 S to 12.5 S suggesting the formation of a complex at a SHMT phosvitin
molar ratio of 2: 1. Based on steady-state fluorescence quenching measurements
an association constant of 2.4 ± 0.2 ×105 M-1 at 25°C was obtained for the
interaction of phosvitin with SHMT. The temperature dependency of the
association constant in the range 15-35°C

suggests the involvement of ionic forces in the
interaction. The thermal inactivation of SHMT followed first order kinetics. In
the presence of phosvitin the rate constant decreased and half time increased.
The circular dichroism measurements suggest that phosvitin interaction does not
involve pyridoxal phosphate binding domain of the enzyme. Although minor changes
in the secondary structure of the enzyme were observed, the environment around
aromatic amino acids did not change significantly.
 
Date 2012-12-31T19:08:55Z
2012-12-31T19:08:55Z
1999-04
 
Type Article
 
Identifier 0975-0959 (Online); 0301-1208 (Print)
http://hdl.handle.net/123456789/15430
 
Language en_US
 
Rights CC Attribution-Noncommercial-No Derivative Works 2.5 India
 
Publisher NISCAIR-CSIR, India
 
Source IJBB Vol.36(2) [April 1999]