Wan L, Gijzen M, Van Huystee R B
Department of Plant Sciences, University of Western Ontario, London, Canada.
Biochem Cell Biol. 1994 Sep-Oct;72(9-10):411-7. doi: 10.1139/o94-055.
Cationic peanut peroxidase (CPrx) from a cell suspension culture is N-glycosylated at Asn60, Asn144, and Asn185. All three N-glycans are complex type and galactose rich, and show heterogeneity in length and ConA (concanavalin A) binding property. The glycan heterogeneity causes a polymorphism of the enzyme. Based on its behavior on ConA columns, CPrx can be grouped into two fractions: nonbinding (CPrx-) and binding (CPrx+) types. A synchronously cosecreted beta-galactosidase has been discovered in the culture medium; there are two isozymes of 60 kDa (pI 7.3) and 66 kDa (pI 7.6). This beta-galactosidase has been partially purified by a combination of ion-exchange and size-exclusion chromatographies and preparative isoelectrofocusing. In vitro experiments indicate that the cosecreted beta-galactosidase is able to convert peroxidase from CPrx- to CPrx+ and may, to some extent, contribute to the glycan heterogeneity of peroxidase in the cell culture.
来自细胞悬浮培养物的阳离子花生过氧化物酶（CPrx）在Asn60、Asn144和Asn185处进行N-糖基化。所有这三种N-聚糖均为复合型且富含半乳糖，并在长度和伴刀豆球蛋白A（ConA）结合特性方面表现出异质性。聚糖的异质性导致该酶具有多态性。根据其在ConA柱上的行为，CPrx可分为两个组分：不结合型（CPrx-）和结合型（CPrx+）。在培养基中发现了一种同步共分泌的β-半乳糖苷酶；有两种同工酶，分子量分别为60 kDa（pI 7.3）和66 kDa（pI 7.6）。这种β-半乳糖苷酶已通过离子交换色谱、尺寸排阻色谱和制备性等电聚焦相结合的方法进行了部分纯化。体外实验表明，共分泌的β-半乳糖苷酶能够将过氧化物酶从CPrx-型转化为CPrx+型，并可能在一定程度上导致细胞培养物中过氧化物酶的聚糖异质性。
