Penicillopepsin amino acid sequence

The amino acid sequences of aspergillopepsin I, penicillopepsin, rhizopuspepsin, endothiapepsin, candidapepsin, mucorpepsin, porcine pepsin, and human cathepsin D are aligned. These enzymes are classified into two groups (class I and II). Class I enzymes have... 

It is clear that a great deal of work is still required in the field of acid proteases before we reach the level of understanding attained for other groups of proteolytic enzymes. Fortunately the amino acid sequence work on at least three enzymes—pepsin, chymosin, and penicillopepsin— is well advanced, and complete three-dimensional structures should become available in the near future. A tentative structure for rhizopus-pepsin has been obtained, but in the absence of sufficient sequence information interpretation of the electron density maps is difficult. We can... 

A number of chemical approaches have been used in the design of renin inhibitors. In the absence of the purified enzyme, most of the early search for inhibitors was carried out using crude renin preparations. The amino acid sequences of mouse, rat and human renin were obtained later on using either the traditional isolation and sequencing techniques or cDNA methodology. Various three-dimensional models of renin were constructed in the early stages, based on the x ray structures of other similar aspartyl proteases, for example endothia-pepsin and penicillopepsin. Later on, the X ray crystal structure of recombinant human renin was reported. The inhibitor design process has been based on some of these models. 

In addition, there is an overall 32% identity of amino acid sequence between penicillopepsin and porcine pepsin a tentative sequence alignment of these two enzymes is given in Table I using this sequence numbering of porcine pepsin (5). These facts indicate that the fungal enzyme penicillopepsin is an evolutionary homologue of the mammalian acid proteases. 

Figure 3. Stereo-drawing of the main polypeptide chain in penicillopepsin. The circles represent a-carbon positions and only every 10th residue has been numbered (corresponding to the numbering of porcine pepsin (5). The regions of high amino-acid sequence homology (see Table I) are drawn in dark lines. The bilobal feature of the molecule is evident from this drawing the active site is located in the groove that separates the two lobes.

Penicillopepsin (0.2 mg) was incubated with Leu-Tyr-Leu (3.2 /nmoles) in 1 ml pyridine-acetate buffer (0.05M in acetate) pH 3.6 at 35° C for 24 hr. The products were separated by high-voltage electrophoresis at pH 3.1 and pH 1.9. Ninhydrin positive bands were eluted, hydrolyzed, and quantitated by amino acid analysis. Identification was made by sequence analysis by standard procedures (details to be published by Takahashi and Hofmann). 

Fig. 16.2. A section of the alignment of sequences of aspartic proteinases achieved by comparing the three-dimensional structures using COMPARER [14]. HIV human immunodeficiency virus RSV Rous sarcoma virus APE endothiapepsin APP penicillopepsin APR rhizopuspepsin PEP hexagonal porcine pepsin CHY calf chymosin. The last letter refers to the amino (N) or car-boxy (C) terminal domains of the pepsins. The coordinates of the three-dimensional structures were obtained from the PDB databank [24]. The amino acid code is the standard one-letter code (see Appendix C) formatted using the following conventions [7] ...

Penicillopepsin is an acid protease produced by the mold Penicillium janthinellum at pH s less than 4.1 (1). Enzyme production occurs after the mycelial growth has ceased and sporulation has begun (2). The specificity and catalytic mechanism of penicillopepsin are very similar to those of porcine pepsin (3). The two active site aspartic acid residues, Asp-32 and Asp-215, occur in peptide sequences of at least eight amino acid residues which are almost identical in penicillopepsin, pepsin and chymosin (1,4-10). 

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