Transaminase bacterial

Induction of extrahepatic mdoleamine dioxygenase (which catalyzes the same reaction as tryptophan dioxygenase, albeit by a different mechanism) by bacterial lipopolysaccharides and mterferon-y may result in the production of relatively large amounts of kynurenine and hydroxykynurenine in tissues that lack the enzymes for onward metabolism. Kidney has kynurenine transaminase activity, and therefore extrahepatic metabolism of tryptophan may result in significant excretion of kynurenic and xanthurenic acids, even when vitamin Bg nutrition is adequate. 

Streptococcus pneumoniae Infection with Streptococcus pneumoniae may cause both toxic liver damage and pneumococcal hepatitis with focal necroses, leading to the corresponding laboratory findings. In lobar pneumonia, jaundice (= biliary pneumonia) frequently occurs in the so-called grey hepatization stage. In addition to predominantly bacterial haemolytic jaundice, increased transaminases (20%) and cholestasis (10%) are found. The condition always regresses completely. A liver abscess induced by pneumococci is a rare event. (3-5, 9)... 

We have previously described the isolation and cloning of genes encoding microbial L-amino acid transaminases [40], and the use of site-directed mutagenesis to enhance enzyme function [41]. The reversibility of the reaction has frequently been considered a drawback of transaminase commercial application because it results in reduced yields and complicates product isolation. Through molecular cloning we have constructed bacterial strains that effectively eliminate this concern by removal of the keto acid by-product, and thereby significantly increase the reaction yield. 

Cefaclor (Ceclor, Raniclor) [Anribioric/Cephalosporin-2nd Generation] Uses Bacterial Infxns of die upper lower resp tract, skin, bone, luinary tract, abd, gynecologic system Action 2nd-gen cephalosporin X cell wall syndi Dose Adults. 250-500 mg PO dd XR 375-500 mg bid Peds. 20-40 mg/kg/d PO - 8-12 h X renal impair Caution [B, +] Contra Cephalosporin allergy Disp Caps, tabs, susp SE D, rash, eosinophilia, T transaminases Interactions T Bleeding W/ andcoagulants T neplirotox W/ aminoglycosides, loop diuredcs T... 

Jung MJ, Metcalf BW. Catalytic inhibition of gamma-aminobutyric acid - alpha-ketoglutarate transaminase of bacterial origin by 4-aminohex-5-ynoic acid, a substrate analog. Biochem Biophys Res Commun 1975 67 301-306. 

This molecule specifically and irreversibly inhibits y-aminobutyrate-a-ketoglutarate transaminase. The Ki for this molecule is 2.8 ixM, some three orders of magnitude lower than the Km for the natural substrate, y-aminobutyrate. The ti/2 for inactivation of the bacterial enzyme is 9 min at 0.3 fuM gabaculine. As expected, gabaculine is not an irreversible inhibitor of the enzyme in the pyridoxamine form, and the mechanism of the irreversible inhibition by gabaculine is completely in accord with the hypothesis that enzymic conversion before inhibition. The possible mechanisms proposed for the inhibition are those in Eq. (5). ... 

Some nonproteinogenic amino acids, produced enzymatically, are shown in Table 29.4 for example, L-homophenylalanine, a key intermediate of levetiracetam and brivaracetam applicable as antiepileptic drugs, or D-fluoroalanine, a key intermediate of antibiotics inactivating the bacterial D-alanine transaminase. In Table 29.4 a selection of proteinogenic and nonproteinogenic amino acids, the used biocatalysts, synthesis strategies, and the substrates used are listed. 

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