The B1-immunoreactive proteins of the perinatal submandibular gland: similarity to the major parotid gland protein, RPSP.
The B1-immunoreactive proteins of type III cells of the perinatal rat submandibular gland are immunologically cross-reactive with proteins of both the sublingual and parotid glands; in particular, protein SMG-A appears similar to a major parotid protein. We isolated SMG-A and the parotid protein (known as M1 or leucine-rich protein), prepared polyclonal antibodies to them, and compared their biochemical properties and immunological reactivities. They were identical in their molecular weight on SDS-PAGE (23.5 kDa), tenacious binding to Affi-gel Blue, isoelectric point (pH 4.53), and proteolysis to a 14 kDa peptide: Antibodies to SMG-A showed reactivity with protein SMG-C, a product of the neonatal type I cells, as well as with proteins SMG-B1 and SMG-B2, contrasted with the absence of reactivity of anti-M1 IgG with these proteins. Anti-M1 reacted with the "parotid secretory protein" (PSP) of the mouse, and M1 appears to be the homologue, in the rat, of mouse PSP.
Department of Anatomy, Howard University College of Medicine, Washington, DC 20059.
W D
WD
Ball
A R
AR
Hand
J E
JE
Moreira
J M
JM
Iversen
M R
MR
Robinovitch
D000818:Animals; D000831:Animals, Newborn; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism; D006868:Hydrolysis; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010306:Parotid Gland / Q000737:chemistry / Q000648:ultrastructure; D011817:Rabbits; D051381:Rats; D012471:Salivary Proteins and Peptides / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D012967:Sodium Dodecyl Sulfate; D013045:Species Specificity; D013361:Sublingual Gland / Q000737:chemistry / Q000648:ultrastructure; D013363:Submandibular Gland / Q000737:chemistry* / Q000254:growth & development / Q000648:ultrastructure
C511597:Bpifa2 protein, mouse; C511598:Bpifa2 protein, rat; D012471:Salivary Proteins and Peptides; C072564:Smgb Protein, rat; D012967:Sodium Dodecyl Sulfate; D010450:Endopeptidases