Proteolytic activity in the maize pollen wall

Abstract

A new protease from maize (Zea mays L.) pollen is described. It was purified using gel filtration, ion exchange and high performance liquid chromatography. SDS‐PAGE and HPLC showed that the enzyme has a dimeric structure of M, ca 60,000. Inhibitor investigations indicated an aspartic acid residue in its active site. The optimum pH for maize pollen aspartic proteinase activity was 5.6, and the optimum temperature was 45°C. The enzyme is easily eluted from the pollen grains and, as confirmed by enzymoblotting after isoelectric focusing, it is located in the pollen wall. Similar to metallo‐proteinases, its activity is inhibited by Zn2+. The pL value for purified aspartic proteinase, as estimated after IEF, was 5.0. Two‐dimensional electrophoresis analysis of proteins eluted from maize pistils suggests that the enzyme digests the proteins and may be involved in pollen‐tube germination. The properties of serine and aspartic proteinases from maize pollen are compared.

Plant aspartic proteinases: enzymes on the way to a function

“…A number of aspartic proteinases have been detected or purified from monocotyledonous (e.g. barley, maize, rice and wheat) ( Doi et al 1980; Belozersky et al 1989; Sarkkinen et al 1992; Radlowski et al 1996) and dicotyledonous plants (e.g. Arabidopsis , Brassica, castor bean, cardoon, cocoa, figleaf gourd, kidney bean, orange, spinach, tobacco, tomato) ( García‐Martinez and Moreno 1986; Mikkonen 1986; Rodrigo et al 1989; Heimgartner et al 1990; Rodrigo et al 1991; Biehl et al 1993; D'Hondt et al 1993; Stachowiak et al 1994; Kuwabara and Suzuki 1995; Veríssimo et al 1996; Hiraiwa et al 1997; Mutlu et al 1998) ( Table 1).…”

“…Ramalho‐Santos et al (1997) have demonstrated the specific localization of the aspartic proteinases from cardoon in the epidermal cells of the stigma and style. Radlowski et al (1996) have purified an aspartic proteinase from maize pollen, while other groups have purified enzymes from leaves of tomato and tobacco ( Rodrigo et al 1989, 1991), or detected aspartic proteinase in leaves of citrus and spinach ( García‐Martinez and Moreno 1986; Kuwabara and Suzuki 1995).…”

“…The localization of the Arabidopsis , cardoon and castor bean aspartic proteinases in the protein bodies of seeds, or parts of flowers, has been confirmed using immunohistochemical techniques and subcellular fractionation ( Hiraiwa et al 1997; Ramalho‐Santos et al 1997; Mutlu et al 1999). The aspartic proteinases from tobacco and tomato and Nepenthes are found secreted ( Juniper et al 1989; Rodrigo et al 1989, 1991), while the enzyme in maize pollen is believed to be in the cell wall ( Radlowski et al 1996). An aspartic proteinase from spinach has also been localized to photosystem II membranes of plastids ( Kuwabara and Suzuki 1995), an unusual site for an enzyme with an acidic pH optimum.…”

Purification and characterization of an aspartic protease from potato leaves

“…Plant APs are found in distinct parts of different plants. APs have been isolated from seeds (Doi et al 1980; Belozersky et al 1989; Stachowiak et al 1994; Asakura et al 1995; D'Hondt et al 1997; Hiraiwa et al 1997; Mutlu et al 1998; Mutlu and Gal 1999), grains (Runeberg‐Roos et al 1991; Sarkkinen et al 1992), flowers (Heimgartner et al 1990; Cordeiro et al 1994a,b; Veríssimo et al 1996; Ramalho‐Santos et al 1997), pollen (Radlowski et al 1996) and leaves (Rodrigo et al 1989, 1991; Kuwabara and Suzuki 1995; Schaller and Ryan 1996). It is not clear what the respective functions of plant aspartic proteinases are in different tissues of different plants.…”

Relación estructura-función de cirsina, una proteasa aspártica de <i>Cirsium vulgare</i>, y compuestos peptídicos derivados con actividad biológica

“…Las PAs se han identificado en una amplia variedad de especies del reino vegetal (Simões and Faro, 2004;Rawlings et al, 2012) y se han aislado de diferentes tejidos, tales como semillas, hojas, flores, raíces y tubérculos: i) semillas de Arabidopsis thaliana (Mutlu and Gal, 1999), arroz (Doi et al, 1980;Asakura et al, 1997), cebada (Runeberg-Roos et al, 1991;Kervinen et al, 1999), trigo (Belozersky, Mikhail A. Sarbakanova and Dunaevsky, 1989;Timotijević et al, 2006;Tamura et al, 2007), cáñamo (St. Angelo et al, 1970), girasol (Park et al, 2000) pepino y calabaza (Wilimowska-Pelc, A Polanowski et al, 1983;Polanowski et al, 1985); ii) hojas de planta de tomate (Rodrigo et al, 1989); iii) hojas y tubérculos de planta de papa (Guevara et al, 1999(Guevara et al, , 2001; iv) polen de maíz (Radlowski et al, 1996) y v) flores de cardos (Tamer, 1993;Faro et al, 1995;Veríssimo et al, 1996;Domingos et al, 2000;Llorente et al, 2004;Vairo Cavalli, 2005;Sidrach et al, 2006), entre otras.…”