Extracytoplasmic space

The last mediator of gastric secretion in the parietal cell is an H+,K+-ATPase (proton or acid pump) which is a member of the phosphorylating class of ion transport ATPases. Hydrolysis of ATP results in ion transport. This chemical reaction induces a conformational change in the protein that allows an electroneutral exchange of cytoplasmic H+ for K+. The pump is activated when associated with a potassium chloride pathway in the canalicular membrane which allows potassium chloride efflux into the extracytoplasmic space, and thus results in secretion of hydrochloric acid at the expense of ATP breakdown. The activity of the pump is determined by the access of K+ on this surface on the pump. In the absence of K+, the cycle stops at the level of the phosphoenzyme [137]. 

Enzymes Peroxidases (C 2.4) M/F ER, dictyosomes and Golgi vesicles, vacuoles and vacuole membrane, lysosomes, plasma membrane, extracytoplasmic space... 

Phenol oxidases (C 2.3.1) M/F Microbodies, peroxisomes, cytoplasm, extracytoplasmic space... 

Coniferin glucosidase (D 22.2.3) F Extracytoplasmic space (cell wall bound )... 

Edeine A, gramicidin S, alamethicin, enniatin B (D 23) F Extracytoplasmic space... 

The secondary compounds or enzymes present in the extracytoplasmic space, e.g., the constituents of the cell wall, either are synthesized at the plasma membrane (like cellulose) or they are secreted into the noncytoplasmic lumen of ER or dictosomes and transported to the extracytoplasmic space by vesicles derived from these organelles (like cell wall matrix polysaccharides and enzymes involved in lignification). 

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