生物化学技术

Almost one-third of the proteins synthesized in the cytosol of cells ends up in membranes or outside the cell. Secretory polypeptides are synthesized as precursor proteins that carry N-terminal signal sequences. Secretion is catalyzed by the “translocase” that comprises a channel-cl ...

Protein import and export pathways are driven by protein translocases, often comprised of multiple subunits, and usually conserved across a range of organisms. Protein import into mitochondria is fundamental to eukaryotic organisms and is initiated when substrate proteins are tr ...

One of the major challenges in the post-genomic era with hundreds of genomes sequenced is the annotation of protein structure and function. Computational predictions of subcellular localization are an important step toward this end. The development of computational tools that pred ...

Plastids are a heterogeneous family of organelles found ubiquitously in plants and algal cells. Most prominent are the chloroplasts, which carry out such essential processes as photosynthesis and the biosynthesis of fatty acids as well as of amino acids. As mitochondria, chloroplasts a ...

I have tried to cover the minimal properties of the prolific number of protein secretion systems identified presently, particularly in Gram negative bacteria. New systems, however, are being reported almost by the month and certainly I have missed some. With the accumulating evidence one r ...

Protein transport across cellular membranes represents an unknown, possibly significant drain on the total energy pool. Many protein transport systems utilize a mixture of energetic inputs, with contributions from both NTP hydrolysis and transmembrane electrochemical gra ...

In eukaryotic cells, roughly one-fourth of all mRNAs code for secretory and membrane proteins. This class of proteins must first be segregated to the endoplasmic reticulum, where they are either translocated into the lumen or inserted into the lipid bilayer. The study of these processes has lo ...

Secretory and membrane proteins that are destined for intracellular organelles in eukaryotes are first synthesized at the endoplasmic reticulum (ER) and are then delivered to their final destinations. The ER contains high concentrations of molecular chaperones and folding enzy ...

Vesicle SNAREs (v-SNAREs) are included with high fidelity into each transport vesicle generated in the cell. These SNAREs determine the fate of vesicles, as they are the key factors deciding with which compartment a particular vesicle will fuse. The mechanism of high fidelity inclusion of SN ...

In eukaryotic cells, N-glycosylation is typically the most common protein modification that occurs in the endoplasmic reticulum (ER) lumen. N-glycosylation is facilitated by a large heterologous protein complex called the oligosaccharyltransferase (OST) that allows the att ...

Immunofluorescence microscopy of cultured cells often gives poor preservation of delicate structures. We have obtained dramatically improved results with a simple modification of a standard protocol. Cells growing on a coverslip are rapidly dehydrated in a cold organic solvent a ...

During the evolution of eukaryotic cells, the majority of mitochondrial genes have been transferred to the nuclear genome with the consequence that most mitochondrial proteins have to be imported into the organelle. This process occurs usually in a post-translational manner. In order to ...

The MIA40 pathway is a novel import pathway in mitochondria specific for cysteine-rich proteins of the intermembrane space (IMS). The newly synthesised precursors are trapped in the IMS by a disulfide relay mechanism that involves introduction of disulfides from the sulfhydryl oxida ...

Protein targeting in both eukaryotic and prokaryotic cells is often directed by a signal sequence located at the amino-terminus of the protein. In eukaryotes, proteins that are sorted into different compartments of the cell, such as endoplasmic reticulum, mitochondria, and chloropla ...

Proteins that are less than 10kDa in size are easily purified under denaturing conditions and can often be refolded by removal of the denaturing agents. The purified small membrane proteins are competent for membrane insertion when the denaturing agent is diluted out and a membranous system ...

Urinary steroid profiling provides quantitative information on the steroid biosynthetic and catabolic pathways. It is essential for identification of inborn errors of steroid metabolism, and useful in other disorders with altered steroid secretion. A general method is detail ...

The background to the physiological production of glucocorticoids is described as well as their concentrations in some biological fluids. Detailed methods are described for the collection, storage, and preparation of samples and for the immunoassay techniques for some common ste ...

This chapter describes how adrenocorticotropin (ACTH) can be measured in biological fluids. The principle can be applied to similar peptide hormones. Following an introduction of the principle of the method, details are given on sample collection and storage, and materials required. D ...

In the clinical laboratory the reproductive hormones are probably the most commonly measured hormones after the thyroid hormones. More than 300 laboratories participate in the UK National External Quality Control Scheme. In addition, investigations into reproduction and fert ...

The commonly used laboratory investigations for the diagnosis and management of thyroid disorders are the thyroid hormones, thyroxine and triiodothyronine and the pituitary hormone, thyrotrophin (TSH). Simple, readily available radioimmunoassay methods for the measure ...