Biomaterial Database

Spinach threonine dehydratase. Inhibition by L-cysteine and D-cysteine. 1978

A Di Stefano, and R Pagani, and E Marinello

L-threonine deaminase from spinach is inhibited by D- and L-cysteine. The inhibition patterns by D-cysteine and by L-cysteine are non-competitive. The value of Ki for D-cysteine and L-cysteine is of the same order of magnitude. Inhibitions by L-isoleucine and L-cysteine are additional. These results indicate that inhibition by L-cysteine occurs on a site of enzyme which is different from the binding site for L-isoleucine and L-valine. Probably L-cysteine and D-cysteine form the thiazolidinic ring with a PLP mole. Which is not costituent of the active site, but located in a different region.

UI	MeSH Term	Description	Entries
D007532	Isoleucine	An essential branched-chain aliphatic amino acid found in many proteins. It is an isomer of LEUCINE. It is important in hemoglobin synthesis and regulation of blood sugar and energy levels.	Alloisoleucine,Isoleucine, L-Isomer,L-Isoleucine,Isoleucine, L Isomer,L-Isomer Isoleucine
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010944	Plants	Multicellular, eukaryotic life forms of kingdom Plantae. Plants acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations. It is a non-taxonomical term most often referring to LAND PLANTS. In broad sense it includes RHODOPHYTA and GLAUCOPHYTA along with VIRIDIPLANTAE.	Plant
D003545	Cysteine	A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.	Cysteine Hydrochloride,Half-Cystine,L-Cysteine,Zinc Cysteinate,Half Cystine,L Cysteine
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D013237	Stereoisomerism	The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Molecular Stereochemistry,Stereoisomers,Stereochemistry, Molecular,Stereoisomer
D013913	Threonine Dehydratase	A pyridoxal-phosphate protein that catalyzes the deamination of THREONINE to 2-ketobutyrate and AMMONIA. The role of this enzyme can be biosynthetic or biodegradative. In the former role it supplies 2-ketobutyrate required for ISOLEUCINE biosynthesis, while in the latter it is only involved in the breakdown of threonine to supply energy. This enzyme was formerly listed as EC 4.2.1.16.	Threonine Deaminase,Threonine Dehydrase,Threonine Ammonia-Lyase,Ammonia-Lyase, Threonine,Deaminase, Threonine,Dehydrase, Threonine,Dehydratase, Threonine,Threonine Ammonia Lyase