Proteins multifunctional

In animals, acetyl-CoA carboxylase (ACC) is a filamentous polymer (4 to 8 X 10 D) composed of 230-kD protomers. Each of these subunits contains the biotin carboxyl carrier moiety, biotin carboxylase, and transcarboxylase activities, as well as allosteric regulatory sites. Animal ACC is thus a multifunctional protein. The polymeric form is active, but the 230-kD protomers are inactive. The activity of ACC is thus dependent upon the position of the equilibrium between these two forms ... 

Like HATs, most functional HDACs are embedded in large multifunctional protein complexes, which also contain other chromatin modifying enzymes and coregulator proteins [1]. 

Multifunctional protein complex in the ER membrane. It translocates secretoiy proteins across and integrates membrane proteins into the ER membrane. The proteinconducting channel protein Sec61p is the most important component of the translocon. 

Multifunctional Proteins Catalyze the Early Reactions of Pyrimidine Biosynthesis... 

The chain shortening pathway has not been characterized in detail at the enzymatic level in insects. It presumably is similar to the characterized pathway as it occurs in vertebrates. These enzymes are a partial P-oxidation pathway located in peroxisomes [29]. The key enzymes involved are an acyl-CoA oxidase (a multifunctional protein containing enoyl-CoA hydratase and 3-hy-droxyacyl-CoA dehydrogenase activities) and a 3-oxoacyl-CoA thiolase [30]. These enzymes act in concert to chain shorten acyl-CoAs by removing an acetyl group. A considerable amount of evidence in a number of moths has accumulated to indicate that limited chain shortening occurs in a variety of pheromone biosynthetic pathways. 

Lee, L., Kelly, R.E., Pastra-Landis, S.C., and Evans, D.R. (1985) Oligomeric structure of the multifunctional protein CAP that initiates pyrimidine biosynthesis in mammalian cells. Proc. Natl. Acad. Sci. USA 82, 6802-6806. 

Skulachev [117] proposed that the released cytochrome c oxidizes superoxide and, by this, exhibits an antioxidant function. This proposal was supported by recent experimental findings by Atlante et al. [118], who suggested that cytochrome c released from mitochondria by oxygen species protected mitochondria through a feedback-like process oxidizing superoxide. The most important physiological inhibitor of apoptosis is multifunctional protein Bcl-2,... 

Noiva, R., Lennarz, W. J., Protein disulfide isomerase. A multifunctional protein resident in the lumen of the endoplasmic reticulum, /. Biol. Chem. 267 (1992),... 

In viruses where the genome is contained within a single nucleic acid molecule, translation produces a large multifunctional protein, a polyprotein, which is then cleaved enzymatically to produce a number of distinct proteins. In viruses where the genome is distributed over a number of molecules, several mRNAs are produced, each being translated into separate proteins. After translation they may be glycosylated using host enzymes. 

Nyabi et al. (162) demonstrated that PSs with mutated Asp residues are catalyti-cally inactive. Unexpectedly, these mutated PSs are still partially processed into amino- and carboxy-terminal fragments by a presenilinase-like activity and are able to rescue PEN2 expression and nicastrin glycosylation, and then they become incorporated into large 440-kDa complexes, demonstrating that the catalytic activity of PS and its other functions in the generation, stabilization, and transport of the y-secretase complex can be separated and extends the concept that PSs are multifunctional proteins (162). 

The processes of fatty acid biosynthesis are catalysed by the enzyme fatty acid synthase. In animals, this is a multifunctional protein containing all of the catalytic activities required, whereas in... 

Fatty acid synthesis is catalysed in animals by the enzyme fatty acid synthase, which is a multifunctional protein containing all of the catalytic activities required. Bearing in mind the necessity to provide a specific binding site for the various substrates involved, and then the fairly complex sequence of reactions carried out, it raises the question of just how it is possible for this process to be achieved at the enzymic level. Nature has devised an elaborate but satisfyingly simple answer to this problem. 

Adhesive proteins provide the connections between the various components of the extracellular matrix. Important representatives include laminin and fibronectin (see B). These multifunctional proteins simultaneously bind to several other types of matrix component. Cells attach to the cell surface receptors in the ECM with the help of the adhesive proteins. 

This enzyme [EC 2.4.2.18], also referred to as phospho-ribosyl-anthranilate pyrophosphorylase, catalyzes the reaction of anthranilate with phosphoribosylpyrophos-phate to produce A-5 -phosphoribosylanthranilate and pyrophosphate. In certain species, this enzyme is part of a multifunctional protein, together with one or more other components of the system for the biosynthesis of tryptophan (i.e., indole-3-glycerol-phosphate synthase, anthranilate synthase, tryptophan synthase, and phos-phoribosylanthranilate isomerase). 

Aspartate kinase [EC 2.T.2.4], also known as asparto-kinase, catalyzes the reaction of aspartate with ATP to produce 4-phosphoaspartate and ADP. The enzyme isolated from E. coli is a multifunctional protein, also exhibiting the ability to catalyze the reaction of homoserine with NAD(P) to produce aspartate 4-semialdehyde and NAD(P)H (that is, the activity of homoserine dehydrogenase, EC 1.1.1.3). 

Lithium Mechanism of action uncertain suppresses inositol signaling and inhibits glycogen synthase kinase-3 (GSK-3), a multifunctional protein kinase No significant antagonistic actions on autonomic nervous system receptors or specific CNS receptors no sedative effects Bipolar affective disorder-prophylactic use can prevent mood swings between mania and depression Oral absorption, renal elimination half-life 20 h. narrow therapeutic window (monitor blood levels) Toxicity Tremor, edema, hypothyroidism, renal dysfunction, dysrhythmias pregnancy category D Interactions Clearance decreased by thiazides and some NSAIDs... 

Additional information <1> (<1> isozyme of calmodulin-dependent multifunctional protein kinase II in smooth-muscle [5] <1> caldesmon is not a substrate of smooth-muscle myosin light-chain kinase [3] <1> no substrates are bovine cardiac C-protein, bovine brain fodrin, rabbit skeletal muscle glycogen synthase, phosphorylase B, troponon (I -I- T -I- C), actin, tropomyosin, smooth-muscle actin, filamin, vinculin, cr-actinin, protamine or phosvitin [1]) [1-3]... 

Ikebe, M. Reardon, S. Scott-Woo, G.C. Zhou, Z. Koda, Y. Purification and characterization of calmodulin-dependent multifunctional protein kinase from smooth muscle isolation of caldesmon kinase. Biochemistry, 29, 11242-11248 (1990)... 

ATP -I- L-aspartate = ADP -I- 4-phospho-L-aspartate (The enzyme from E. coli is a multifunctional protein, which also catalyses the reaction of EC 1.1.1.3 homoserine dehydrogenase)... 

The Fatty Acid Synthase of Some Organisms Consists subunit are inactivated by mutation, palmitate synthe-of Multifunctional Proteins sis is only modestly reduced. 

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