Cysteine proteases protease actinidin

Corresponding equations were derived for the cysteine proteases ficin, actinidin, bromelain B and D, and the serine proteases subtilisin, chymotrypsin, and trypsin. In all cases, the coefficient of the electronic a term is around 0.4-0.7. Whereas the other regression coefficients in equations (16) and (17) are also relatively similar, the constant terms of both equations differ by about 1.8 log units, which indicates that the lower lipophilicity of the mesyl group, as compared with a much more lipophilic benzoyl group, is responsible for the lower binding affinities of the mesyl amides. To prove this hypothesis, a series of (4-X-Phe)-CONHCH2COO-pyrid-3-yl analogs 12 was synthesized and tested. As expected, lipophilicity determines the structure-activity relationship in this part of the molecules (equation IS). " " ... 

Cysteine proteases are a class of enzymes that have been widely studied over the years. The overall principles of substrate recognition, catalysis, and inhibition are now reasonably well documented. This enzyme class includes the plant proteases such as papain, actinidin, and bromelain, and several mammalian lysosomal cathe-psins. By far the majority of the literature reports dealing with cysteine proteases describe results obtained with the enzyme papain, because it is considered to be the archetype of this enzyme class. 

Solanum tuberosum (potato) Potato cysteine protease Actinidin [27 nMl, [185-... 

Cysteine proteases are so called because of a critical cysteine involved (together with an adjacent histidine) in the catalytic mechanism. Cysteine proteases include papain-related proteases, calpain-related proteases and the caspases. Papain-like cysteine proteases include the plant enzymes actinidin, aleurain, bromelain, caricain, chymopapain, ficin and papain and the lysosomal cathepsins B, C, H, K, L and S. Cathepsin C is multimeric (MW -200,000), but the other papain-related proteases are monomeric with MWs of about 20,000-35,000. While cathepsin C is a dipeptidyl aminopeptidase, the other enzymes are endopeptidases. Cathepsin B is an endopeptidase and a dipeptidyl carboxypeptidase. Cathepsin H is an endopeptidase and an aminopeptidase. In higher animals, cathepsin B generates peptides from antigens for presentation to T cells by the major histocompatibility... 

Kiwifruit is the most well-known crop in the genus Actinidia. Although Actinidia fruit sales in the international market are dominated by a single kiwifruit cultivar Actinidia deliciosa Hayward, there are a considerable number of cultivars and selections in the genus that have widely diverse shape, size, and hairiness. They also offer a wide variation in sensory attributes such as flesh color, flavor, and taste, and in nutritional attributes such as the vitamin C level and carotenoid content. The level of actinidin, which is a cysteine protease in kiwifruit, also varies greatly among cultivars. This chapter reviews available information related to several important components, allergenic properties, and health benefits of Actinidia fruits. 

The extent of the irritation caused by kiwifruit might be affected by several factors, including oxalate concentration, the shape of the raphides, the presence of cysteine protease actinidin (Boyes et al, 1997), and the fruit acidity. Considerable variation exists among species in oxalate content and in the raphide shape. Total oxalate concentrations in fruits are estimated to be 37-65 mg/100 g FW in A. deliciosa (Perera et al, 1990), 18 5 mg/100 g FW iaA. (Rassam and Laing, 2005), and 5.0-8.5 mg/100 gFW in A. arguta... 

Actinidin is a cysteine protease that requires a free sulfhydryl group for activity (Arcus, 1959 McDowall, 1970). This protease is composed of 220 amino acid residues with molecular mass of 23,500 (Came and Moore, 1978). The amino acid sequence of the enzyme shows considerable homology with papain, a well-known cysteine protease in immature papaya fruit (Came and... 

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