Enzyme degradation subcellular localization

Okita, T. W., Greenberg, E., Kuhn, D. N., and Preiss, J. 1979. Subcellular localization of the starch degradative and biosynthetic enzymes of spinach leaves. Plant Physiol. 64,187-192. 

The subcellular localization of the starch biosynthetic and degradative enzymes of spinach leaves was carried out by measuring the distribution of the enzymes in a crude chloroplast pellet and in separated components of a protoplast lysate. The enzymes which were involved in the syntheses of starch were detected in the chloroplasts, whereas some of the enzymes involved in the degradation of starch were mainly in the soluble protein fraction but were also found in the chloroplast. The digestion pattern of the amylase on amylopectin as substrate indicated that the enzyme was an a-amylase from its endo-lytic activity, but displayed properties unlike the typical a-amylase isolated from endosperm tissue. A time-sequence analysis of the starch digestion pattern in germinating... 

The various APS and PAPS hydrolases described in Secticm III could be of some significance in the regulation of sulfate assimilation. However, since the synthesis of APS and PAPS are known to occur in chloroplasts, these possibilities must remain speculative until the subcellular localization of the enzymes catalyzing Eqs. (4)-(6) are established especially since Burnell and Anderson (1973a) reported that nonspecific 3 -nucleotidase is not associated with chloroplasts. Recently, Sawhney and Nicholas (1976b) have reported that particulate fractions from Anabaena degrade PAPS to sulfate. ADP sul-furylase, which catalyzes the reaction... 

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