New Observations on the Substrate Specificity of Cathepsin C (Dipeptidyl Aminopeptidase I)

McDonald, J. Ken; Zeitman, Benjamin B.; Reilly, Thomas J.; Ellis, Stanley

doi:10.1016/s0021-9258(18)83453-6

Cited by 219 publications

(19 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Antibodies against cathepsin C were provided by E Mainferme and prepared as described previously (33). Briefly, rabbits were immunized with cathepsin C purified from rat liver according to the method of McDonald et al (34). The IgG fraction was subsequently used and specifically immunoprecipitated multiple forms of the enzymes (see reference 33 for a detailed description of the antigen).…”

Section: Antibodiesmentioning

confidence: 99%

Polarized secretion of lysosomal enzymes: co-distribution of cation-independent mannose-6-phosphate receptors and lysosomal enzymes along the osteoclast exocytic pathway.

Baron

Neff

Brown

et al. 1988

The Journal of Cell Biology

204

View full text Add to dashboard Cite

Abstract. The osteoclast is a polarized cell which secretes large amounts of newly synthesized lysosomal enzymes into an apical extracellular lacuna where bone resorption takes place. Using immunocytochemical techniques, we have localized the cationindependent mannose-6-phosphate (Man6P) receptor and lysosomal enzymes in this cell type in order to determine the expression and distribution of this receptor and its ligands. The results demonstrate that the osteoclast expresses large amounts of immunoreactive cation-independent Man6P receptors, despite the fact that most of the lysosomal enzymes it synthesizes are secreted. The lysosomal enzymes and the receptors are co-distributed along the exocytic pathway, i.e., the endoplasmic reticulum, including the perinuclear envelope, the Golgi stacks as well as numerous small transport vesicles that appear to fuse with the ruffled border membrane. Within the Golgi complex, the receptors and lysosomal enzymes were found distributed in two predominant patterns; (a) in all the cisternae, from cis to trans, or (b) predominantly in cis-and trans-Golgi cisternae, with the middle Golgi cisternae being unstained or depleted in antigen. This pattern suggests that enzymes and receptors traverse the Golgi from cis to trans and preferentially accumulate in cis-and in trans-cisternae. This study therefore suggests that, in the osteoclast, Man6P receptors are involved in the vectorial transport and targeting of newly synthesized lysosomal enzymes, presumably via a constitutive pathway, to the apical membrane where they are secreted into the bone-resorbing compartment. This mechanism could insure polarized secretion of lysosomal enzymes into the bone-resorbing lacuna.

show abstract

Section: Antibodiesmentioning

confidence: 99%

Polarized secretion of lysosomal enzymes: co-distribution of cation-independent mannose-6-phosphate receptors and lysosomal enzymes along the osteoclast exocytic pathway.

Baron

Neff

Brown

et al. 1988

The Journal of Cell Biology

204

View full text Add to dashboard Cite

show abstract

“…The anion binding site is a lysyl residue which apparently has a counterpart in ACE (Lifschitz & Levitzki, 1976;Bünning et al, 1978;Bünning & Riordan, 1981b). Cathepsin C belongs to a second group of anionactivated enzymes (McDonald et al, 1966(McDonald et al, , 1969Gorter & Gruber, 1970) where anions solely affect Ku. Whether anions activate by affecting kQil or KM, in all cases studied the activation is accompanied by a shift of the pH-activity profile toward the alkaline pH region.…”

Section: Easmentioning

confidence: 99%

Activation of angiotensin converting enzyme by monovalent anions

Bünning¹,

Riordan²

1983

Biochemistry

106

View full text Add to dashboard Cite

The angiotensin converting enzyme catalyzed hydrolysis of furanacryloyl-Phe-Gly-Gly is activated by monovalent anions in the order C1- greater than Br- greater than F- greater than NO3- greater than CH3COO-. In the alkaline pH region, increasing anion concentrations decrease the KM but do not change the kcat. This behavior is characteristic of an ordered bireactant mechanism in which the anion binds to the enzyme prior to the substrate. At acidic pH values, however, the anion activation is a result of both a decrease in KM and an increase in kcat, implying a bireactant mechanism in which anion and substrate bind randomly. For both the ordered and the bireactant mechanisms the anion serves as an essential activator. The effect of chloride on enzyme activity was studied over the pH range 5-10 under kcat/KM conditions and demonstrates that the apparent chloride binding constant increases from 3.3 mM at pH 6.0 to 190 mM at pH 9.0. The kcat vs. pH profile exhibits two pK values of 5.6 and 9.6, while the variation of KM with pH is characterized by a pK of 8.9 and a 2-fold increase between pH 6.5 and 7.5. The chloride activation of the hydrolysis of furanacryloyl-Phe-Gly-Gly is compared with that of the physiological substrates angiotensin I and bradykinin.

show abstract

“…The comparison of the substrate specificity of the porcine brain DAP and the four previously described DAPs is another important discriminating feature. DAP I (Me Donald et al, 1969b) and DAP III (Lee et al, 1982) both hydrolyze angiotensin II whereas the porcine brain DAP does not degrade this peptide. DAP II is inhibited by cations such as Na+, K+, and Tris (Me Donald et al, 1968), and its substrate specificity is restricted to tripeptides.…”

Section: Discussionmentioning

confidence: 99%

Purification and characterization of an enkephalin-degrading dipeptidyl-aminopeptidase from porcine brain

Cherot¹,

Fournié‐Zaluski²,

Laval³

1986

Biochemistry

View full text Add to dashboard Cite

A porcine brain dipeptidyl-aminopeptidase (DAP) has been purified more than 2400-fold from a crude mitochondrial fraction containing synaptosomes. This enzyme catalyzes the release of free Tyr-Gly from Leu-enkephalin (Km = 2.5 microM) with an optimal activity between pH 6.0 and pH 8.0. The enzyme appears homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis devoid of detectable contaminating aminopeptidase activities. The native enzyme is a monomeric protein with a molecular weight of 51,000 +/- 1,000 and an isoelectric point of 4.6 +/- 0.1. This enzyme cosediments with synaptosomes on a Ficoll-sucrose gradient and is partially associated with synaptic plasma membranes. Its activity is inhibited by the metal-chelating agents ethylenediaminetetraacetate and o-phenanthroline. It is not inhibited by the OH-reactive agent phenylmethanesulfonyl fluoride and SH-reactive agents such as p-(chloromercuri)benzoate and N-ethylmaleimide. Among the various biologically active peptides tested, the purified enzyme releases efficiently the N-terminal dipeptide moiety from enkephalins, Trp-Met-Asp-Phe-NH2 (CCK4), and Gly-Trp-Met-Asp-Phe-NH2 (CCK5). At variance, the native peptides CCK8, substance P, neurotensin, and angiotensin II are not cleaved by the DAP. This enzyme is different from other unspecific DAPs, as well as from enkephalin-degrading DAPs previously reported, by its molecular weight and substrate specificity.

show abstract

New Observations on the Substrate Specificity of Cathepsin C (Dipeptidyl Aminopeptidase I)

Cited by 219 publications

References 53 publications

Polarized secretion of lysosomal enzymes: co-distribution of cation-independent mannose-6-phosphate receptors and lysosomal enzymes along the osteoclast exocytic pathway.

Polarized secretion of lysosomal enzymes: co-distribution of cation-independent mannose-6-phosphate receptors and lysosomal enzymes along the osteoclast exocytic pathway.

Activation of angiotensin converting enzyme by monovalent anions

Purification and characterization of an enkephalin-degrading dipeptidyl-aminopeptidase from porcine brain

Contact Info

Product

Resources

About