Adenylyltransferase

As expected, in vitro transcription assays involving PARP-1, NAD, and PARC illustrate these predicted outcomes (Kim et al, 2004). Even when driven by a transcriptional activator, such as estradiol-bound estrogen receptor, transcription is repressed when PARP-1 is added to chromatin templates. The repression is reversed by NAD+, and the NAD+-dependent effects are reversed by PARC (Kim et al, 2004). This system for transcriptional control shifts new importance onto the enzymes responsible for synthesis of NAD+ in the nucleus, such as nicotinamide mononucleotide adenylyltransferase-1 (Magni et al, 2004). Because NAD+ facilitates the decompaction of chromatin and the derepression of transcription, nuclear NAD+ biosynthetic enzymes may play critical roles as cofactors. 

This enzyme [EC 2.7.7.42], also known as glutamateiam-monia-ligase adenylyltransferase, plays a key role in controlling bacterial nitrogen metabolism by controlling the state of adenylylation of glutamine synthetase. 

This enzyme [EC 2.7.7.1], also known as NAD pyropho-sphorylase, catalyzes the reaction of ATP with nicotinamide ribonucleotide to produce NAD+ and pyrophosphate (or, diphosphate). Nicotinate nucleotide is also a substrate. Nicotinate-nucleotide adenylyltransferase [EC 2.7.7.18] uses nicotinate ribonucleotide as the pyridine substrate, thereby producing deamido-NAD and pyrophosphate. 

ADP as a substrate in enzyme reactions, ADENYLATE KINASE (or MYOKINASE) ATP SYNTHASE CREATINE KINASE NUCLEOSIDE DIPHOSPHATE KINASE PHOSPHOGLYCERATE KINASE PYRUVATE KINASE RIBONUCLEOTIDE REDUCTASE SULFATE ADENYLYLTRANSFERASE (ADP) [ADP]/[ATP] ratio,... 

SULFATE ADENYLYLTRANSFERASE (ADP) ADRENODOXIN ADSORPTION ABSORPTION BIOMINERALIZATION MICELLAR CATALYSIS LANGMIUR ISOTHERM Adsorption coefficient LANGMUIR ISOTHERM Adsorption of gases,... 

RNA POLYMERASES SELENOPHOSPHATE SYNTHETASE SHIKIMATE KINASE SULFATE ADENYLYLTRANSFERASE TUBULIN TYROSINE LIGASE UBIQUITIN-PROTEIN LIGASES d-XYLULOKINASE ATP-dependent protease La,... 

CYTOCHROME P-450 REDUCTASE DIHYDROOROTATE OXIDASE FMN ADENYLYLTRANSFERASE GLUTAMATE SYNTHASE GLYCOLATE OXIDASE (S)-2-HYDROXY-ACID OXIDASE l-LACTATE DEHYDROGENASE (CYTOCHROME)... 

SQUALENE SYNTHASE SULFATE ADENYLYLTRANSFERASE UBIQUITIN-PROTEIN LIGASES PYROPHOSPHATE FRUOTOSE-6-PHOS-PHATE 1-PHOSPHOTRANSFERASE PYROPHOSPHOMEVALONATE DECARBOXYLASE... 

SULFATE ADENYLYLTRANSFERASE SULFATE ADENYLYLTRANSFERASE (ADR) Sulfhydryl-disulfide interchange,... 

Structures of several important aminoglycoside antibiotics. Ring II is 2-deoxystreptamine. The resemblance between kanamycin and amikacin and between gentamicin, netilmicin, and tobramycin can be seen. The circled numerals on the kanamycin molecule indicate points of attack of plasmid-mediated bacterial transferase enzymes that can inactivate this drug. , , and , acetyltransferase , phosphotransferase , adenylyltransferase. Amikacin is resistant to modification at , , , and . 

M FIGURE 22-7 Second level of regulation of glutamine synthetase covalent modifications, (a) An adenylylated Tyr residue, (b) Cascade leading to adenylylation (inactivation) of glutamine synthetase. AT represents adenylyltransferase UT, uridylyltransferase. Details of this cascade are discussed in the text. 

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