Subunit structure of karatasin, the proteinase isolated from Bromelia plumieri (karatas).

Abstract

Close to 15% of the karatasin proteinase activity in the fruit juice of Bromelia plumieri (karatas) is present outside dialysis Visking tubing in 7 days in 0.2 M acetate buffer (pH) 3.5 or 6.5) containing phenyl mercuric acetate. The small proteinase(s), distinct from the 85% activity in juice due to nondialysable karatasin with a reported Mr of 24,868, separates across Spectrapore (13 kDa) membranes but not across Spectrapore with 3.5 kDa average pore diameter. The dialyzed proteinase is named karatasin-D (K-D). Purified non-Dialysable karatasin can be dissociated to what seems to be K-D by incubation in a buffer solution, containing SDS and 2-mercaptoethanol with phenyl mercuric acetate, in dialysis experiments for 8 days at room temperature using Spectrapore 13 kDa tubing. Thus, native karatasin in B. plumieri fruit juice seem to be the result of association of 2 small molecular mass K-D subunits, linked together by disulfide bonds and electrostatic forces, in equilibrium with small amounts of free K-D molecules. The amino acid composition and partial sequence of karatasin up to the 14th position from the amino terminus have discrete analogies with papain and with stem bromelain.

Macrodontin, a New Protease Isolated From Fruits of Pseudananas Macrodontes (Morr.) Harms (Bromeliaceae)

“…Bromelain, obtained from stems (EC 3.4.22.32) and fruits (EC 3.4.22.33) of pineapple (Ananas comosus), is the most renowned protease of the family (Murachi 1976;Ota et al 1985;Napper et al 1994;Rowan and Buttle 1994). Additionally, proteases from fruits of other species of Bromeliaceae have been isolated and characterized: Bromelia pinguin (Toro-Goyco et al 1968, B. hemisphenca, B. palmen and B. sylvestris (Cruz et al 1974;Hemhdez Arana et al 1983), B. plumieri (Montes et al 1990), B. balansae, B. laciniosa and B. serra (Caffini et al 1989) and B. hieronymi (Priolo et al 1991).…”

Functional and Rheological Properties of Piñuela (Bromelia karatas) in Two Ripening Stages.

“…The samples were sheared at a constant shear rate of 400 s -1 for 3 min, after which a downward ramp to 0 s -1 and another upward ramp until 400 s -1 were accomplished. The average shear stress values of these two ramps were used to calculate the juice viscosity and to build the corresponding rheogram, which gives information about the flow-behavior of the different samples [20]; eqs (2) to (7).…”

“…However, in Mexico, the varieties of this species have received attention by some researchers. Other research [5], for example, studied the antioxidant activity of the leaves, while in other studies [7], they isolated and characterized a protease enzyme (karatasin) contained in the fruit. In Colombia, the only interest has been on its exotic aroma, where researches focused on studying their organoleptic properties [8,9].…”

Comparison of Two Cysteine Endopeptidases from Pseudananas macrodontes (Morr.) Harms (Bromeliaceae)

“…Bromeliaceae is a plant family whose members usually produce large amounts of proteases with no apparent function in plant growth and development (Boiler, 1986). To date a number of cysteine endopeptidases from species belonging to Bromeliaceae have been isolated and characterized: stem and fruit bromelain (EC 3.4.22.32 and EC 3.4.22.33,respectively), ananain (EC 3.4.22.31) and comosain, obtained from Ananas comosus (Murachi, 1976;Ota et al, 1985;Napper ef al., 1994;Rowan et al, 1994;Lee et al, 1997), pinguinain (EC 3.4.22.33, formerly EC 3.4.99.18), isolated from Bromelia pinguin (Toro-Goyco et al, 1968, as well as proteases from fruits of B. hemispherica, B. palmen and B. sylvestris (Cruz et al, 1974;Hernández Arana et al, 1983), Β. plumleri (Montes et al, 1990), B. hieronymi (Priolo et al, 1991), B. balansae (Pardo et al, 2000) and Pseudananas macrodontes (Natalucci et al, 1996;López et al, 2000).…”