Flexible Enantioselectivity of Tryptophanase Attributable to Benzene Ring in Heterocyclic Moiety of D-Tryptophan

نویسندگان

  • Akihiko Shimada
  • Haruka Ozaki
چکیده

The invariance principle of enzyme enantioselectivity must be absolute because it is absolutely essential to the homochiral biological world. Most enzymes are strictly enantioselective, and tryptophanase is one of the enzymes with extreme absolute enantioselectivity for L-tryptophan. Contrary to conventional knowledge about the principle, tryptophanase becomes flexible to catalyze D-tryptophan in the presence of diammonium hydrogenphosphate. Since D-amino acids are ordinarily inert or function as inhibitors even though they are bound to the active site, the inhibition behavior of D-tryptophan and several inhibitors involved in this process was examined in terms of kinetics to explain the reason for this flexible enantioselectivity in the presence of diammonium hydrogenphosphate. Diammonium hydrogenphosphate gave tryptophanase a small conformational change so that D-tryptophan could work as a substrate. As opposed to other D-amino acids, D-tryptophan is a very bulky amino acid with a benzene ring in its heterocyclic moiety, and so we suggest that this structural feature makes the catalysis of D-tryptophan degradation possible, consequently leading to the flexible enantioselectivity. The present results not only help to understand the mechanism of enzyme enantioselectivity, but also shed light on the origin of homochirality.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Synthesis and Docking Analysis of New Heterocyclic System N1, N4-bis ((2-chloroquinolin-3-yl) methylene) benzene-1, 4-diamine as Potential Human AKT1 Inhibitor

Abstract: Objective(s): In recent years, the chemistry of 2-chloroquinoline-3-carbaldehydes have received considerable attention owing to their synthetic and effective biological importance which exhibits a wide variety of biological activity, N1,N4-bis((2-chloroquinolin-3-yl)methylene)benzene-1,4-diamine derivatives that synthesized from 2-chloroquinoline-3-carbaldehydes may have biological ef...

متن کامل

Synthesis and Docking Analysis of New Heterocyclic System N1, N4-bis ((2-chloroquinolin-3-yl) methylene) benzene-1, 4-diamine as Potential Human AKT1 Inhibitor

Abstract: Objective(s): In recent years, the chemistry of 2-chloroquinoline-3-carbaldehydes have received considerable attention owing to their synthetic and effective biological importance which exhibits a wide variety of biological activity, N1,N4-bis((2-chloroquinolin-3-yl)methylene)benzene-1,4-diamine derivatives that synthesized from 2-chloroquinoline-3-carbaldehydes may have biological ef...

متن کامل

Tryptophan Metabolism in Man.

The amino acid tryptophan is unique because it contains the indole nucleus and because it is metabolized in man through several different biochemical pathways to a number of specific products. It is the precursor of serotonin and 5-hydroxyindoleacetic acid. In addition, after cleavage of the indole ring, it may be metabolized by way of the kynurenine pathway to 3-hydroxyanthranilic acid and ult...

متن کامل

Biological Importance of the Indole Nucleus in Recent Years: A Comprehensive Review

Heterocyclic compounds are those cyclic compounds in which one or more of the ring carbons are replaced by another atom. The non-carbon atoms in such rings are referred to as ‘‘heteroatoms.’’ Such bicyclic heterocyclic compounds containing pyrrole ring with benzene ring fused to a,b-position are known as Indoles. Indole has a benzene ring and pyrrole ring sharing one double bond. It is a hetero...

متن کامل

Tryptophan Metabolism in Man * ALFRED

The amino acid tryptophan is unique because it contains the indole nucleus and because it is metabolized in man through several different biochemical pathways to a number of specific products. It is the precursor of serotonin and 5-hydroxyindoleacetic acid. In addition, after cleavage of the indole ring, it may be metabolized by way of the kynurenine pathway to 3-hydroxyanthranilic acid and ult...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره 2  شماره 

صفحات  -

تاریخ انتشار 2012