Biomaterial Database

L-histidine ammonia-lyase from a T-strain Mycoplasma (Ureaplasma urealyticum). 1977

F Ajello, and N Romano, and M F Massenti

L-histidine ammonia-lyase (E.C. 4.3.1.3) activity was shown to occur in cell-free extracts of Ureaplasma urealyticum. The activity of the crude enzyme depends on the presence of thiol compounds. However, higher than optimal concentrations of reduced glutathione, were shown to cause some inhibition of enzyme activity. This enzymatic reaction is characterized by a "lag" phase, whose duration depends on assay conditions. The substrate saturation curve shows a sigmoidal pattern probably due to the presence (in crude enzyme preparations) of some inhibiting impurity which reversibly combines with the substrate. Statistically significant increases of enzyme activity were demonstrated in crude enzyme preparations obtained from mycoplasma cells grown in broth medium supplemented with 16 mM L-histidine.

UI	MeSH Term	Description	Entries
D002474	Cell-Free System	A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)	Cellfree System,Cell Free System,Cell-Free Systems,Cellfree Systems,System, Cell-Free,System, Cellfree,Systems, Cell-Free,Systems, Cellfree
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D005978	Glutathione	A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.	Reduced Glutathione,gamma-L-Glu-L-Cys-Gly,gamma-L-Glutamyl-L-Cysteinylglycine,Glutathione, Reduced,gamma L Glu L Cys Gly,gamma L Glutamyl L Cysteinylglycine
D006638	Histidine Ammonia-Lyase	An enzyme that catalyzes the first step of histidine catabolism, forming UROCANIC ACID and AMMONIA from HISTIDINE. Deficiency of this enzyme is associated with elevated levels of serum histidine and is called histidinemia (AMINO ACID METABOLISM, INBORN ERRORS).	Histidase,Histidinase,Histidine Deaminase,Histidine alpha-Deaminase,Ammonia-Lyase, Histidine,Deaminase, Histidine,Histidine Ammonia Lyase,Histidine alpha Deaminase,alpha-Deaminase, Histidine
D000642	Ammonia-Lyases	Enzymes that catalyze the formation of a carbon-carbon double bond by the elimination of AMMONIA. EC 4.3.1.	Ammonia Lyase,Ammonia-Lyase,Ammonia Lyases,Lyase, Ammonia
D014509	Ureaplasma	A genus of gram-negative, nonmotile bacteria which are common parasitic inhabitants of the urogenital tracts of humans, cattle, dogs, and monkeys.	T-Mycoplasma,Ureaplasma parvum,Ureaplasma urealyticum biovar 1