生物化学技术

Kinetic analyses of lipases and phospholipases must take into account the fact that these enzymes generally catalyze their reactions at a lipid-water interface as opposed to catalysis in a monophasic aqueous environment. This chapter discusses the application of an important tool in t ...

The primary role for lipoprotein lipase (LPL) is hydrolysis of triglycerides in chylomicrons and very low density lipoproteins (VLDL). This enzyme has also been implicated in the process of atherogenesis (for reviews see refs. 1 and 2). Additional enzymatic activities of LPL include retin ...

The lipase gene family comprises three vertebrate genes, lipoprotein lipase (LPL), hepatic lipase (HL) and pancreatic lipase (PL), that are derived from a common ancestral gene. While these lipases are functionally related, considerable evidence indicates that LPL and HL share a higher d ...

In humans, the digestion of dietary triacylglycerols is mediated by two main enzymes, a gastric lipase which is secreted by the chief cells of the fundic mucosa and which acts in the stomach as well as the intestine, and a pancreatic lipase which contributes to the lipid digestion only in the duodenum (1– ...

Lipoprotein lipase (LPL) is an N-inked glycoprotein of approximately 57 kDa that is synthesized by a numbel of tissues, including white and brown adipose tissue, heart, skeletal muscle, neonatal liver and brain (1,2). In these tissues, LPL is synthesized by parenchymal cells and secreted to the s ...

Hepatic lipase (HL) and lipoprotein lipase (LPL) are two lipolytic enzymes that play an important role in the metabolism of circulating lipoproteins. Both enzymes catalyze the esterolysis of fatty acids present at the sn-1 (3) position of triacylglycerols. HL is functional at the lumenal fa ...

The presence of a redundant lipolytic system of bile salt-activated lipase (BAL) and pancreatic lipase results in the concerted action of these lipolytic enzymes during intestinal dietary fat digestion processes (1). Because of its wide substrate reactivity, BAL is involved not only in t ...

The assay of pancreatic triglyceride lipase (PL) is done routinely in clinical laboratories and in research laboratories with an interest in this lipolytic enzyme. The assay requirements differ between these two settings. The clinical laboratory requires automated assays that are ...

The human plasma platelet-activating factor acetylhydrolase (PAF acetylhydrolase, l-alkyl-2-acetyl-glycerophosphocholine esterase, l-alkyl-2-acetyl-sn-glycero-3-phosphocholine acetohydrolase, EC 3.1.1.47) is a phospholipase A2 activity discovered by i ...

Plasmalogens are a unique class of glycerophospholipids (1) characterized by the presence of a vinyl ether substituent at the sn-1 position of the glycerol backbone. Found in all mammalian cells, these phospholipids are especially abundant in brain and heart (1). However, while choline pl ...

Phospholipases A2 (PLA2) are a family of ubiquitous lipolytic enzymes that are found both as intracellular and secreted proteins. Secretory PLA2s are small (14 kDa), homologous proteins that require millimolar Ca2+ for catalytic activity. They can be classified into at least four groups b ...

Lipases are responsible for extracellular degradation and intracellular metabolism of lipids in animals, plants, and microorganisms. The conformational motif of all lipases whose three-dimensional structure has been determined is characterized by an α/β hydrolase fold (1). M ...

Phospholipases are a diverse group of lipolytic enzymes with specificities for different sites on the phospholipid molecule (1). Based on the site of their hydrolytic attack, they can be classified into several groups, among which phospholipase A2 (PLA2), phospholipase C (PLC), and phosp ...

Mammalian acidic lipases belong to a family of lipases that share the ability to maintain activity under acidic conditions. This family includes pre-duodenal lipases and lysosomal lipase and shows no sequence homology with other known lipase families (1,2). Human gastric lipase (glyc ...

Lipolytic enzymes have traditionally been assayed by radiometric and titrimetric methods (1). Radiometric methods are quite sensitive but require expensive radiolabeled substrates and tedious separation of labeled substrate and products. In addition, the safe use of radioac ...

The baculovirus expression system is very convenient to produce recombinant pancreatic lipases and mutants thereof, in substantial amounts (10–50 mg of enzyme per liter of culture) for structure-function studies (see also Chapters 17, 18, and 20 in this volume). Using the naturally occur ...

Lysosomal acid lipase (LAL, EC 3.1.1.13) is a hydrolase essential for the intracellular degradation of lipids derived from plasma lipoproteins (1). LAL is synthesized in most cells and tissues of the human body, including fibroblasts, macrophages and lymphocytes. Although LAL activity is ...

Vascularization is one of the most central processes enabling multicellular life. Owing to the complexity of vascularization regulatory networks, minor control imbalances often have severe pathologic consequences ranging from ischemic diseases to cancer. Tissue enginee ...

Owing to their in vivo-like characteristics, three-dimensional (3 D) multicellular tumor spheroid (MCTS) cultures are gaining increasing popularity as an in vitro model of tumors. A straightforward and simple approach to the cultivation of these MCTS is the hanging-drop method. Cells a ...

Tissue engineering aims to provide a temporary scaffold for repair at the site of injury or disease that is able to support cell attachment and growth while synthesis of matrix proteins and reorganization take place. Although relatively successful, bladder tissue engineering suffers f ...