Processing of rat and human angiotensinogen precursors by microsomal membranes.
We have studied the processing of rat and human angiotensinogen precursors by microsomal membranes as a means of determining the number of asparagine-linked oligosaccharide units per angiotensinogen molecule, and thus the utilization of potential sites of N-glycosylation. Glycosylated, processed forms of angiotensinogen were isolated by chromatography on lentil lectin-Sepharose 4B. 35S-Methionine-labeled precursor and processed forms of angiotensinogen were compared with glycosylated and nonglycosylated 35S-methionine-labeled mature forms of angiotensinogen secreted by hepatoma cells, using immunoprecipitation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. N-Glycosylation of secreted angiotensinogen was inhibited using tunicamycin. For rat angiotensinogen, only 2 of 3 potential sites of N-glycosylation were utilized; in contrast, all 4 potential sites of N-glycosylation of human angiotensinogen were utilized. For neither rat or human angiotensinogen precursor was there any evidence for a prosequence.
D000118:Acetylglucosaminidase; D000808:Angiotensinogen / Q000235:genetics*; D000809:Angiotensins / Q000235:genetics*; D000818:Animals; D002460:Cell Line; D002474:Cell-Free System; D006801:Humans; D007425:Intracellular Membranes / Q000201:enzymology*; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D008861:Microsomes / Q000201:enzymology*; D008862:Microsomes, Liver / Q000201:enzymology*; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D013045:Species Specificity
D000809:Angiotensins; D012333:RNA, Messenger; D000808:Angiotensinogen; D000118:Acetylglucosaminidase; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase