Microbial L-phenylalanine ammonia-lyase. Purification, subunit structure and kinetic properties of the enzyme from Rhizoctonia solani.

The Biochemical Journal
K K Kalghatgi, P V Subba Rao

Abstract

1. Phenylalanine ammonia-lyase (EC 4.3.1.5) was purified to homogeneity from the acetone-dried powders of the mycelial felts of the plant pathogenic fungus Rhizoctonia solani. 2. A useful modification in protamine sulphate treatment to get substantial purification of the enzyme in a single-step is described. 3. The purified enzyme shows bisubstrate activity towards L-phenylalanine and L-tyrosine. 4. It is sensitive to carbonyl reagents and the inhibition is not reversed by gel filtration. 5. The molecular weight of the enzyme as determined by Sephadex G-200 chromatography and sucrose-density-gradient centrifugation is around 330000. 6. The enzyme is made up of two pairs of unidentical subunits, with a molecular weight of 70000 (alpha) and 90000 (beta) respectively. 7. Studies on initial velocity versus substrate concentration have shown significant deviations from Michaelis-Menten kinetics. 8. The double-reciprocal plots are biphasic (concave downwards) and Hofstee plots show a curvilinear pattern. 9. The apparent Km value increases from 0.18 mM to as high as 5.0 mM with the increase in the concentration of the substrate and during this process the Vmax, increases by 2-2.5-fold. 10. The value of Hill coefficient is 0.5. 11. St...Continue Reading

Citations

May 23, 2016·Applied Microbiology and Biotechnology·Anna M KotMarek Kieliszek
Jul 12, 2012·Mycobiology·Min Woo HyunSeong Hwan Kim
Jul 1, 1992·World Journal of Microbiology & Biotechnology·S Kawasaki WatanabeA Lopez-Munguia
May 22, 2013·Critical Reviews in Biotechnology·Jian Dong CuiZhi Lei Tan
Oct 11, 2017·Current Medicinal Chemistry·Vadim S PokrovskyElena V Lukasheva
Apr 1, 1988·Applied and Environmental Microbiology·S A OrndorffD R Durham
May 1, 1976·Journal of Bacteriology·K K Kalghatgi, P V Subba Rao

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