Some properties of an exocellular lipase fromRhizopus arrhizus

Abstract

Rhizopus arrhizus, a mold of the mucor family, excretes an active lipase when cultured properly. This lipase has a mol wt of 43,000 and a high carbohydrate content, Upon storage at 4C in aqueous solution, lipase I is slowly converted by proteolysis to a more cationic form, lipase II, which has a lower mol wt (32,000) and no carbohydrate.Rhizopus lipase shows the same positional specificity on long chain triglycerides as pancreatic lipase; it has no preferential side chain specificity against oleic vs. palmitic acid. Like pancreatic lipase,Rhizopus lipase acts on micelles of short chain triglycerides and is inhibited by high concentrations of bile acids; however, in the presence of deoxycholate,Rhizopus lipase does not require added Ca++ for full activity.

Isolation and Characterization of an Extracellular Lipase from the Conidia of Neurospora cvassa

“…This result suggests that the N . crassa lipase preferentially cleaves the primary ester group of triacylglycerols in the same way as pancreatic lipase (Brockerhoff & Jensen, 19746) and the lipases from Rhizopus arrhizus (Benzonana, 1974), Candida deformans (Mudherwa et al, 1985) and different Afcaligenes strains (Kokusho et al, 1982).…”

Esterification patterns of lipases for synthesizing tricaproylglycerols in organic solvent

“…For further enzymatic reaction, sn-1,3-dicaprin must be nonenzymatically isomerized to α,β-dicaprin. (18). Only the resulting α,β-dicaprin can be esterified to tricaprin (14,15).…”

“…Probably, the main reason for the slow reaction from dicaprin to tricaprin is that 1,3-specific lipase cannot esterify capric acid to the sn-2 position of sn-1,3-dicaprin, although sn-1,3-dicaprin was fruitfully produced. Thus, for further synthesis to tricaprin, sn-1,3-dicaprin must be isomerized to α,β-dicaprin nonenzymatically (18). This nonenzymatic isomerization must be the rate-limiting step of tricaprin synthesis.…”

“…With three lipases from each respective group, interesterification patterns of tripalmitin with capric acid were investigated (16). The results showed that synthetic or interesterification patterns between the same 1,3-specific groups (Group II and Group III) in hydrolyzing the triglyceride (15)(16)(17)(18) are not the same in organic solvent (1,16).…”

Metabolism During Asexual Sporulation in Rhizopus arrhizus (Fischer)

“…Calculations based on the percentage of protein in the total spore dry weight at the end of sporulation (60 h) indicated that 1.6 mg protein was incorporated in the spores during the sporulation process. Since extracellular enzymes have been described for R. arrhizus (Benzonana, 1974;Marshall, 1973), it was also possible that the decrease in mycelial proteins was due to the excretion of proteins into the medium. The medium protein content increased by 1.8 mg per culture from 30 to 60 h. From the above information and taking into account the amount of protein extracted from the unfractured spores, it was calculated that 12.7 yo of the protein lost during sporulation could be accounted for by means other than degradation.…”