Human serum albumin

About: Human serum albumin is a research topic. Over the lifetime, 9402 publications have been published within this topic receiving 269029 citations. The topic is also known as: serum albumin & ALB.

Production of correctly processed human serum albumin in transgenic plants.

Abstract: We have used a modified CaMV 35S promoter to direct the expression of chimaeric genes encoding human serum albumin (HSA) in transgenic potato and tobacco plants. To secrete the protein, either the human prepro-sequence or the signal sequence from the extracellular tobacco protein PR-S was used. We demonstrate secretion of HSA with both types of signal sequences in transgenic leaf tissue and in suspension cultures. HSA produced in transgenic potato plants was purified to chromatographic homogeneity. N-terminal amino acid sequence analysis revealed that the processing of the precursor protein was dependent on the type of signal sequence. Expression of the human preproHSA gene lead to partial processing of the precursor and secretion of proHSA. Fusion of HSA to the plant PR-S presequence resulted in cleavage of the presequence at its natural site and secretion of correctly processed HSA that is indistinguishable from the authentic human protein.

Structure and ligand binding properties of human serum albumin

Abstract: UNLABELLED 1 INTRODUCTION Serum albumin possesses a unique capability to bind, covalently or reversibly, a great number of various endogenous and exogenous compounds Several different transport proteins exist in blood plasma but albumin only is able to bind a wide diversity of ligands reversibly with high affinity The subject of the present thesis is these binding properties In 1981 the author proposed in a review a model for binding of ligands to serum albumin In the model, binding of ligands to at least 6 distinct regions was considered The purpose of the experimental work described here was to test the validity of the model This was done by performing a large number of competition experiments From these new data a revised model for ligand binding is presented 2 STRUCTURE AND CONFORMATIONAL CHANGES OF SERUM ALBUMIN Human serum albumin consists of 585 amino acids forming a single polypeptide of known sequence A number of well characterized genetic variants have been reported The physico-chemical characteristics of the protein are well-established By contrast, the complete secondary and tertiary structures are not known; information about major structural features only has been obtained The albumin molecule seems to have an overall ellipsoidal shape (about 140 x 40 A) and to be composed of domains On the basis of the amino acid sequence, Brown (1977a) proposed a 3-domain model for the protein Each domain is believed to consist of 6 helices forming a hydrophobic channel with basic and hydrophobic amino acid residues placed at the ends Experimental data, however, indicate that the domains cannot be identical Long-chain fatty acid ions are proposed to bind with high affinity within the channels The ability to fluctuate between isomeric forms in aqueous solution could assist in adapting the albumin molecule to bind ligands with a diverse nature with high affinity This possibility is discussed on the basis of several physico-chemical techniques including hydrogen-deuterium exchanges Also the importance of the N-B transition for ligand binding is considered 3 PRELIMINARY BINDING MODEL OF SERUM ALBUMIN Single binding of ligands to serum albumin is usually described as high-affinity binding to one or two sites and weaker binding to a larger number of sites In this chapter, the original binding model for high-affinity binding is elaborated Region 1 seems to be specific for binding of one, or possibly two, ions of long-chain fatty acids Region 2 is somewhat less specific and includes binding of octanoate, tryptophan, chlorazepate, thyroxine, p-iodobenzoate and possibly also chloride Region 3 accommodates bilirubin, Phenol Red, Bromophenol Blue and iopanoate Region 4 is a special site for strong binding of metal ions such as Cu++ and Ni++ Evidence is presented for placing the primary haemin site in a separate region (no 5) The existence of additional binding regions, well-suited for high-affinity binding of drugs, is discussed